diff --git a/crates/engine/src/cmd/page.rs b/crates/engine/src/cmd/page.rs
index 2a676d91a..0553d4c0f 100644
--- a/crates/engine/src/cmd/page.rs
+++ b/crates/engine/src/cmd/page.rs
@@ -12,7 +12,7 @@ use crate::{CmdError, CmdResult, CommandSpec, Selection, Session, p};
 pub fn specs() -> Vec<CommandSpec> {
     vec![
         CommandSpec::new("layout.margins", "Margins", "Layout › Page Setup", margins).params(
-            r#"{"preset"?: "normal|narrow|moderate|wide|mirrored|office2003", "top"?: pt, "bottom"?: pt, "left"?: pt, "right"?: pt, "gutter"?: pt}"#,
+            r#"{"preset"?: "normal|narrow|moderate|wide|mirrored|office2003", "top"?: pt, "bottom"?: pt, "left"?: pt, "right"?: pt, "gutter"?: pt, "mirror"?: bool}"#,
         ),
         CommandSpec::new("layout.orientation", "Orientation", "Layout › Page Setup", |s, v| {
             let land = match p::str(v, "value") {
@@ -396,9 +396,10 @@ fn margins(s: &mut Session, v: &Value) -> CmdResult {
     if !margins_fit((cur.page_w, cur.page_h), (t, b, l, r), gutter.unwrap_or(cur.gutter)) {
         return Err(CmdError::Params("margins leave no room for text".into()));
     }
-    // A preset picks mirrored or not; plain numbers (a ruler drag, an agent) keep the setting.
-    if preset.is_some() {
-        s.doc.settings.mirror_margins = preset == Some("mirrored");
+    // A preset picks mirrored or not, as does `mirror` (Page Setup's Multiple pages); plain numbers
+    // alone (a ruler drag, an agent) keep the setting.
+    if let Some(on) = p::bool(v, "mirror").or(preset.map(|k| k == "mirrored")) {
+        s.doc.settings.mirror_margins = on;
     }
     with_sect(s, |x| {
         x.margin_top = t.max(0.0);
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index f9b1d2966..d7d4e9ce9 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -1625,6 +1625,15 @@ fn page_setup_and_breaks() {
     assert_eq!(s.doc.sections().len(), 2);
     assert_eq!(s.layout().pages.len(), 2);
     assert!(s.run("layout.margins", &json!({"left": 1000.0})).is_err());
+    // Mirrored margins: from the preset or `mirror` (#1181); plain numbers keep the setting.
+    run(&mut s, "layout.margins", json!({"preset": "mirrored"}));
+    assert!(s.doc.settings.mirror_margins);
+    run(&mut s, "layout.margins", json!({"left": 80.0}));
+    assert!(s.doc.settings.mirror_margins);
+    run(&mut s, "layout.margins", json!({"left": 80.0, "mirror": false}));
+    assert!(!s.doc.settings.mirror_margins && s.doc.last_section.margin_left == 80.0);
+    run(&mut s, "layout.margins", json!({"mirror": true}));
+    assert!(s.doc.settings.mirror_margins);
 }
 
 /// #1433: a custom page size (More Paper Sizes…) sets the section in its orientation, and
diff --git a/crates/layout/src/lib.rs b/crates/layout/src/lib.rs
index efa2f3c5d..1a6f8efed 100644
--- a/crates/layout/src/lib.rs
+++ b/crates/layout/src/lib.rs
@@ -650,6 +650,8 @@ struct Ctx<'a> {
     /// Body blocks that are empty paragraphs carrying only a section break before a continuous
     /// section, in order: they take no room (see [`place_para`]).
     quiet_marks: Vec<usize>,
+    /// Whether even pages are mirrored (mirrored margins, on pages): see [`mirror_even_pages`].
+    mirror: bool,
     /// Cache-key hashes of the table-style text formatting cells were laid out with
     /// ([`Ctx::table_key`]).
     table_keys: Vec<(para::CellText, u64)>,
@@ -1227,17 +1229,21 @@ fn box_float_table_rect(
 ) -> (Rect, Rect) {
     let h = tl.rows.iter().map(|r| r.height).sum::<f32>().clamp(0.0, 100_000.0);
     let w = tl.width.clamp(1.0, 100_000.0);
-    let page_x = |s: &SectionProps| match f.h_rel {
-        Anchor::Page => Some((0.0, s.page_w)),
-        Anchor::Margin => Some((s.margin_left + s.gutter, s.text_width())),
-        _ => None,
+    // Across, as laid out before an even page is mirrored (see `float_rect`).
+    let page_x = |fr: &PageFrame| {
+        let (left, _, shift) = fr.sides();
+        match f.h_rel {
+            Anchor::Page => Some((-shift, fr.sect.page_w)),
+            Anchor::Margin => Some((left - shift, fr.sect.text_width())),
+            _ => None,
+        }
     };
     let page_y = |s: &SectionProps| match f.v_rel {
         Anchor::Page => Some((0.0, s.page_h)),
         Anchor::Margin => Some((s.margin_top, s.text_height())),
         _ => None,
     };
-    let h_area = frame.and_then(|fr| page_x(fr.sect).map(|(a, e)| (a - fr.origin.0, e))).unwrap_or((0.0, width));
+    let h_area = frame.and_then(|fr| page_x(&fr).map(|(a, e)| (a - fr.origin.0, e))).unwrap_or((0.0, width));
     // In a cell an offset from the page or margin has nothing to measure from: the table stands
     // where the text is.
     let (v_area, y_off) = match frame.and_then(|fr| page_y(fr.sect).map(|(a, e)| (a - fr.origin.1, e))) {
@@ -1247,7 +1253,7 @@ fn box_float_table_rect(
     };
     // Nor is there an area to align in: the table starts where the text is.
     let v_align = if frame.is_none() && matches!(f.v_rel, Anchor::Page | Anchor::Margin) { None } else { f.v_align };
-    let x = align_in(h_area, f.x, w, f.h_align) - if f.h_align.is_none() { legacy } else { 0.0 };
+    let x = align_in(h_area, f.x, w, PageFrame::h_align(frame.as_ref(), f.h_align)) - if f.h_align.is_none() { legacy } else { 0.0 };
     let r = clear_of_float_tables(Rect::new(x, align_in(v_area, y_off, h, v_align), w, h), f, legacy, h_area.0, float_tables);
     let [dl, dt, dr, db] = f.dist_from_text();
     (r, r.inset(-dl, -dt, -dr, -db))
@@ -1936,12 +1942,14 @@ fn layout_pass(
         uses_totals: false,
         track_totals: true,
         quiet_marks: Vec::new(),
+        mirror: false,
         table_keys: Vec::new(),
     };
     let sections = doc.sections();
     let web = matches!(opts.view, ViewMode::Web | ViewMode::Draft | ViewMode::Outline);
     let read = opts.view == ViewMode::Read;
     let reflow = web || read;
+    ctx.mirror = doc.settings.mirror_margins && !reflow;
     ctx.quiet_marks = sections
         .windows(2)
         .filter(|w| w[1].1.start == SectionStart::Continuous)
@@ -2478,7 +2486,7 @@ fn body_top_for(ctx: &mut Ctx, sect: &SectionProps, header: Option<u32>) -> f32
     let Some(part) = ctx.doc.parts.get(&id) else { return sect.margin_top };
     let blocks = part.blocks.clone();
     // Placed as `headers_footers` draws it, so page-relative floats wrap the same way.
-    let frame = PageFrame { sect, origin: (sect.margin_left + sect.gutter, sect.header) };
+    let frame = PageFrame { sect, origin: (sect.margin_left + sect.gutter, sect.header), number: 1, mirror: ctx.mirror };
     let track = std::mem::replace(&mut ctx.track_totals, false);
     let h = layout_box(ctx, StoryRef::Part(id), &blocks, &[], sect.text_width(), BoxContext::Other, 0, Some(frame)).height;
     ctx.track_totals = track;
@@ -2505,6 +2513,34 @@ struct PageFrame<'a> {
     sect: &'a SectionProps,
     /// Page position of the box's (0, 0); (0, 0) for body text.
     origin: (f32, f32),
+    /// The page's number: inside and outside are left and right on odd pages, the other way
+    /// round on even ones.
+    number: u32,
+    /// Whether an even page is mirrored ([`mirror_even_pages`]).
+    mirror: bool,
+}
+
+impl PageFrame<'_> {
+    fn even(&self) -> bool {
+        self.number.is_multiple_of(2)
+    }
+
+    /// The widths of the page's left and right margins (the gutter is on the inside), and how
+    /// far [`mirror_even_pages`] moves what is laid out on it.
+    fn sides(&self) -> (f32, f32, f32) {
+        let (inside, outside) = (self.sect.margin_left + self.sect.gutter, self.sect.margin_right);
+        let shift = outside - inside;
+        if self.mirror && self.even() && shift.is_finite() { (outside, inside, shift) } else { (inside, outside, 0.0) }
+    }
+
+    /// Alignment `a` across the page: inside and outside become right and left on an even page.
+    fn h_align(frame: Option<&Self>, a: Option<FloatAlign>) -> Option<FloatAlign> {
+        match a {
+            Some(FloatAlign::Inside) if frame.is_some_and(|f| f.even()) => Some(FloatAlign::End),
+            Some(FloatAlign::Outside) if frame.is_some_and(|f| f.even()) => Some(FloatAlign::Start),
+            a => a,
+        }
+    }
 }
 
 /// A floating (not inline) picture, chart or shape: its size and placement.
@@ -2518,16 +2554,22 @@ fn floating(o: &InlineObject) -> Option<(f32, f32, &Float)> {
 /// to the box itself.
 fn float_rect(frame: Option<PageFrame>, col: (f32, f32), y0: f32, w: f32, h: f32, float: &Float) -> Rect {
     let (w, h) = (w.clamp(1.0, 4000.0), h.clamp(1.0, 4000.0));
-    // Each axis: the reference area's start and extent, in page coordinates.
-    let page_x = |s: &SectionProps| {
-        let left = s.margin_left + s.gutter;
-        match float.h_rel {
-            Anchor::Page => Some((0.0, s.page_w)),
-            Anchor::Margin => Some((left, s.text_width())),
-            Anchor::LeftMargin | Anchor::InsideMargin => Some((0.0, left)),
-            Anchor::RightMargin | Anchor::OutsideMargin => Some((s.page_w - s.margin_right, s.margin_right)),
-            _ => None,
-        }
+    // Each axis: the reference area's start and extent, in page coordinates. Across, as laid out
+    // before an even page is mirrored (less the shift it then gets).
+    let page_x = |f: &PageFrame| {
+        let (s, even) = (f.sect, f.even());
+        let (left, right, shift) = f.sides();
+        let (start, extent) = match float.h_rel {
+            Anchor::Page => (0.0, s.page_w),
+            Anchor::Margin => (left, s.text_width()),
+            Anchor::LeftMargin => (0.0, left),
+            Anchor::RightMargin => (s.page_w - right, right),
+            Anchor::InsideMargin if even => (s.page_w - right, right),
+            Anchor::OutsideMargin if !even => (s.page_w - right, right),
+            Anchor::InsideMargin | Anchor::OutsideMargin => (0.0, left),
+            _ => return None,
+        };
+        Some((start - shift, extent))
     };
     let page_y = |s: &SectionProps| match float.v_rel {
         Anchor::Page => Some((0.0, s.page_h)),
@@ -2536,9 +2578,10 @@ fn float_rect(frame: Option<PageFrame>, col: (f32, f32), y0: f32, w: f32, h: f32
         Anchor::BottomMargin | Anchor::OutsideMargin => Some((s.page_h - s.margin_bottom, s.margin_bottom)),
         _ => None,
     };
-    let hx = frame.and_then(|f| page_x(f.sect).map(|(a, e)| (a - f.origin.0, e))).unwrap_or(col);
+    let hx = frame.and_then(|f| page_x(&f).map(|(a, e)| (a - f.origin.0, e))).unwrap_or(col);
     let vy = frame.and_then(|f| page_y(f.sect).map(|(a, e)| (a - f.origin.1, e))).unwrap_or((y0, 0.0));
-    Rect::new(align_in(hx, float.x, w, float.h_align), align_in(vy, float.y, h, float.v_align), w, h)
+    let h_align = PageFrame::h_align(frame.as_ref(), float.h_align);
+    Rect::new(align_in(hx, float.x, w, h_align), align_in(vy, float.y, h, float.v_align), w, h)
 }
 
 /// Where an object of `size` starts on one axis of `area` (start, extent): at `offset` from the
@@ -2687,7 +2730,7 @@ fn anchor_floats(
     let (col_x, width) = (pb.col_x(), pb.col_w());
     let mut rects = HashMap::new();
     if !pb.web {
-        let frame = PageFrame { sect: pb.sect, origin: (0.0, 0.0) };
+        let frame = PageFrame { sect: pb.sect, origin: (0.0, 0.0), number: pb.number, mirror: ctx.mirror };
         // An object left out of the layout (hidden, or deleted in the final text) is not placed, so
         // it takes no room either.
         let left_out = left_out_objects(ctx.doc, p, None, ctx.opts.show_hidden, ctx.hide_deleted);
@@ -3198,7 +3241,7 @@ fn place_para_in_flow(ctx: &mut Ctx, pb: &mut PageBuilder, p: &Paragraph, block:
         push_para(&mut items, StoryRef::Body, &[block as u32], &pl, l0, l1, x, y, width);
         // Pictures, shapes and text boxes in these lines (web view: floats placed by this piece).
         let at = ObjFrame {
-            page: Some(PageFrame { sect: pb.sect, origin: (0.0, 0.0) }),
+            page: Some(PageFrame { sect: pb.sect, origin: (0.0, 0.0), number: pb.number, mirror: ctx.mirror }),
             col: (x, width),
             para_y: if pb.web { y } else { anchor_y },
             table_chr: None,
@@ -3331,7 +3374,12 @@ fn place_outline_para(ctx: &mut Ctx, pb: &mut PageBuilder, p: &Paragraph, block:
     let y = pb.y + pl.lines.first().map(|f| f.top.max(0.0)).unwrap_or(0.0);
     let mut items = Vec::new();
     push_para(&mut items, StoryRef::Body, &[block as u32], &pl, 0, l1, x, y, width);
-    let at = ObjFrame { page: Some(PageFrame { sect: pb.sect, origin: (0.0, 0.0) }), col: (x, width), para_y: y, table_chr: None };
+    let at = ObjFrame {
+        page: Some(PageFrame { sect: pb.sect, origin: (0.0, 0.0), number: pb.number, mirror: ctx.mirror }),
+        col: (x, width),
+        para_y: y,
+        table_chr: None,
+    };
     let (behind, front) = place_objects(ctx, StoryRef::Body, &[block as u32], &q, &pl, (0, l1), (x, y), &at, &HashMap::new(), 0);
     items.extend(front);
     let children = level < outline::BODY && outline::has_children(&o.levels, block);
@@ -3446,12 +3494,12 @@ fn place_table(ctx: &mut Ctx, pb: &mut PageBuilder, t: &wordcraft_doc::Table, bl
         let legacy = if ctx.doc.settings.compat_mode < 15 { table::first_cell_left_margin(ctx, t) } else { 0.0 };
         let h: f32 = tl.rows.iter().map(|r| r.height).sum();
         if h <= pb.uncapped_bottom() - pb.top + 0.01 {
-            place_floating_table(pb, &tl, &f, legacy, block, body_top);
+            place_floating_table(pb, &tl, &f, legacy, ctx.mirror, block, body_top);
             return;
         }
         // Too tall for a page: Word lets it run across pages like a table in the text, from its
         // own left edge.
-        tl.x = float_table_x(pb, tl.width, &f, legacy) - pb.col_x();
+        tl.x = float_table_x(pb, tl.width, &f, legacy, ctx.mirror) - pb.col_x();
     }
     // A table in the text flow starts below the floating objects in its way.
     below_floats(pb, pb.col_x() + tl.x, pb.col_x() + tl.x + tl.width);
@@ -3553,20 +3601,20 @@ fn table_notes(ctx: &mut Ctx, pb: &mut PageBuilder, items: &[Placed]) {
 
 /// Place floating table `tl` (`w:tblpPr`): at its own position, which takes no room in the text
 /// flow; the text after it wraps around it.
-fn place_floating_table(pb: &mut PageBuilder, tl: &table::TableLayout, f: &TableFloat, legacy: f32, block: usize, body_top: f32) {
+fn place_floating_table(pb: &mut PageBuilder, tl: &table::TableLayout, f: &TableFloat, legacy: f32, mirror: bool, block: usize, body_top: f32) {
     let h: f32 = tl.rows.iter().map(|r| r.height).sum::<f32>().clamp(0.0, 100_000.0);
     let w = tl.width.clamp(1.0, 100_000.0);
     let [dl, dt, dr, db] = f.dist_from_text();
     for attempt in 0..2 {
         let s = pb.sect;
-        let h_area = float_table_h_area(pb, f);
+        let h_area = float_table_h_area(pb, f, mirror);
         // The text a table anchored to it stands in: where the next paragraph starts.
         let v_area = match f.v_rel {
             Anchor::Page => (0.0, s.page_h),
             Anchor::Margin => (s.margin_top, s.text_height()),
             _ => (pb.y, 0.0),
         };
-        let x = float_table_x(pb, w, f, legacy);
+        let x = float_table_x(pb, w, f, legacy, mirror);
         let r = clear_of_float_tables(Rect::new(x, align_in(v_area, f.y, h, f.v_align), w, h), f, legacy, h_area.0, &pb.float_tables);
         // Like Word, a table that doesn't fit below the text before it moves to the next page with
         // its anchor: one placed relative to the paragraph when it would run off the page, one
@@ -3599,20 +3647,28 @@ fn place_floating_table(pb: &mut PageBuilder, tl: &table::TableLayout, f: &Table
     }
 }
 
-/// The area a floating table's `x` is measured in: its start and width on the page.
-fn float_table_h_area(pb: &PageBuilder, f: &TableFloat) -> (f32, f32) {
+/// The page `pb` is filling, for placing floating objects on it (`mirror`: [`Ctx::mirror`]).
+fn page_frame<'a>(pb: &PageBuilder<'a>, mirror: bool) -> PageFrame<'a> {
+    PageFrame { sect: pb.sect, origin: (0.0, 0.0), number: pb.number, mirror }
+}
+
+/// The area a floating table's `x` is measured in: its start and width on the page, as laid out
+/// before an even page is mirrored (see [`float_rect`]).
+fn float_table_h_area(pb: &PageBuilder, f: &TableFloat, mirror: bool) -> (f32, f32) {
     let s = pb.sect;
+    let (left, _, shift) = page_frame(pb, mirror).sides();
     match f.h_rel {
-        Anchor::Page => (0.0, s.page_w),
-        Anchor::Margin => (s.margin_left + s.gutter, s.text_width()),
+        Anchor::Page => (-shift, s.page_w),
+        Anchor::Margin => (left - shift, s.text_width()),
         _ => (pb.col_x(), pb.col_w()),
     }
 }
 
 /// A floating table's left edge on the page (`legacy`: the first cell's left margin before Word
 /// 2013 layout, when an offset places the cell's text).
-fn float_table_x(pb: &PageBuilder, w: f32, f: &TableFloat, legacy: f32) -> f32 {
-    let x = align_in(float_table_h_area(pb, f), f.x, w, f.h_align);
+fn float_table_x(pb: &PageBuilder, w: f32, f: &TableFloat, legacy: f32, mirror: bool) -> f32 {
+    let align = PageFrame::h_align(Some(&page_frame(pb, mirror)), f.h_align);
+    let x = align_in(float_table_h_area(pb, f, mirror), f.x, w, align);
     if f.h_align.is_none() { x - legacy } else { x }
 }
 
@@ -3782,7 +3838,7 @@ fn headers_footers(ctx: &mut Ctx, pages: &mut [Page], sections: &[(usize, &Secti
             && let Some(part) = ctx.doc.parts.get(&id)
         {
             let blocks = part.blocks.clone();
-            let frame = PageFrame { sect, origin: (x, sect.header) };
+            let frame = PageFrame { sect, origin: (x, sect.header), number: page.number, mirror: ctx.mirror };
             let mut items = layout_box(ctx, StoryRef::Part(id), &blocks, &[], w, BoxContext::Other, 0, Some(frame)).items;
             for it in &mut items {
                 it.translate(x, sect.header);
@@ -3796,7 +3852,7 @@ fn headers_footers(ctx: &mut Ctx, pages: &mut [Page], sections: &[(usize, &Secti
             let blocks = part.blocks.clone();
             // The footer's height fixes where it sits, which page-relative floats need.
             let h = layout_box(ctx, StoryRef::Part(id), &blocks, &[], w, BoxContext::Other, 0, None).height;
-            let frame = PageFrame { sect, origin: (x, sect.page_h - sect.footer - h) };
+            let frame = PageFrame { sect, origin: (x, sect.page_h - sect.footer - h), number: page.number, mirror: ctx.mirror };
             let mut items = layout_box(ctx, StoryRef::Part(id), &blocks, &[], w, BoxContext::Other, 0, Some(frame)).items;
             for it in &mut items {
                 it.translate(x, sect.page_h - sect.footer - h);
diff --git a/crates/layout/src/tests.rs b/crates/layout/src/tests.rs
index 53453606b..59e24ee5f 100644
--- a/crates/layout/src/tests.rs
+++ b/crates/layout/src/tests.rs
@@ -3103,7 +3103,7 @@ fn lines_with_tabs_never_shrink() {
     }
 }
 
-fn rect_shape(w: f32, h: f32, float: wordcraft_doc::para::Float) -> InlineObject {
+pub(super) fn rect_shape(w: f32, h: f32, float: wordcraft_doc::para::Float) -> InlineObject {
     InlineObject::Shape {
         kind: wordcraft_doc::para::ShapeKind::Rectangle,
         w,
@@ -3119,7 +3119,7 @@ fn rect_shape(w: f32, h: f32, float: wordcraft_doc::para::Float) -> InlineObject
     }
 }
 
-fn shapes(items: &[Placed]) -> Vec<Rect> {
+pub(super) fn shapes(items: &[Placed]) -> Vec<Rect> {
     items.iter().filter_map(|i| if let Placed::Shape { rect, .. } = i { Some(*rect) } else { None }).collect()
 }
 
diff --git a/crates/layout/src/tests_pages.rs b/crates/layout/src/tests_pages.rs
index 0869bad32..e59a5b8d8 100644
--- a/crates/layout/src/tests_pages.rs
+++ b/crates/layout/src/tests_pages.rs
@@ -53,6 +53,110 @@ fn mirrored_margins_put_the_inside_margin_toward_the_binding() {
     }
 }
 
+#[test]
+fn inside_and_outside_floats_swap_sides_on_even_pages() {
+    // #1181: shapes Word places in the outside margin of a book (mirrored margins) all came out
+    // in the right margin. Inside 108 plus a 10pt gutter, outside 36; the paragraph on page 2
+    // carries the same six shapes as page 1's, told apart by their widths.
+    use super::tests::{rect_shape, shapes};
+    use wordcraft_doc::para::{Anchor, Float, FloatAlign, Wrap};
+    let mut d = Document::from_text("Odd page\nEven page");
+    d.last_section.margin_left = 108.0;
+    d.last_section.margin_right = 36.0;
+    d.last_section.gutter = 10.0;
+    d.settings.mirror_margins = true;
+    if let Some(Block::Para(p)) = d.body.get_mut(1).map(Arc::make_mut) {
+        p.props.page_break_before = Some(true);
+    }
+    let floats = [
+        (Anchor::Margin, Some(FloatAlign::Outside), 0.0),
+        (Anchor::OutsideMargin, Some(FloatAlign::Center), 0.0),
+        (Anchor::InsideMargin, Some(FloatAlign::Center), 0.0),
+        (Anchor::Page, Some(FloatAlign::Inside), 0.0),
+        (Anchor::Page, None, 10.0),
+        (Anchor::LeftMargin, Some(FloatAlign::End), 0.0),
+    ];
+    for block in 0..2 {
+        for (i, (h_rel, h_align, x)) in floats.iter().enumerate() {
+            let f = Float { wrap: Wrap::InFrontOfText, h_rel: *h_rel, h_align: *h_align, x: *x, ..Default::default() };
+            d.insert_object(&Pos::body(block, 0), rect_shape(20.0 + 2.0 * i as f32, 10.0, f), &Default::default()).unwrap();
+        }
+    }
+    // Left edge of shape `i` on an odd and on an even page (page coordinates).
+    let want = |i: usize, even: bool| {
+        let w = 20.0 + 2.0 * i as f32;
+        match (i, even) {
+            (0, false) => 576.0 - w,
+            (0, true) => 36.0,
+            (1, false) => 576.0 + (36.0 - w) / 2.0,
+            (1, true) => (36.0 - w) / 2.0,
+            (2, false) => (118.0 - w) / 2.0,
+            (2, true) => 494.0 + (118.0 - w) / 2.0,
+            (3, false) => 0.0,
+            (3, true) => 612.0 - w,
+            (4, _) => 10.0,
+            (5, false) => 118.0 - w,
+            _ => 36.0 - w,
+        }
+    };
+    let l = lay(&d);
+    assert_eq!(l.pages.len(), 2);
+    for (pi, page) in l.pages.iter().enumerate() {
+        let r = shapes(&page.items);
+        assert_eq!(r.len(), floats.len(), "page {pi}: {r:?}");
+        for (i, f) in floats.iter().enumerate() {
+            let w = 20.0 + 2.0 * i as f32;
+            let got = r.iter().find(|r| (r.w - w).abs() < 0.01).unwrap();
+            let x = want(i, page.number % 2 == 0);
+            assert!((got.x - x).abs() < 0.01, "page {} shape {i} ({:?}): at {}, want {x}", page.number, f, got.x);
+        }
+    }
+    // Without mirrored margins the margins stay put, but inside and outside still follow the
+    // page (ECMA-376 §20.4.3.4): the inside of an even page is its right side.
+    d.settings.mirror_margins = false;
+    let l = lay(&d);
+    let r = shapes(&l.pages[1].items);
+    let at = |w: f32| r.iter().find(|r| (r.w - w).abs() < 0.01).unwrap().x;
+    assert!((at(20.0) - 118.0).abs() < 0.01, "outside of the margins on page 2: {}", at(20.0));
+    assert!((at(26.0) - (612.0 - 26.0)).abs() < 0.01, "inside of page 2: {}", at(26.0));
+    assert!((at(28.0) - 10.0).abs() < 0.01, "{}", at(28.0));
+}
+
+#[test]
+fn outside_floating_tables_swap_sides_on_even_pages() {
+    // #1181, for a floating table (`w:tblpXSpec="outside"`): on page 2 of a book the outside is
+    // the left. One positioned from the page edge stays there on both pages.
+    use wordcraft_doc::para::{Anchor, FloatAlign};
+    use wordcraft_doc::props::TableFloat;
+    let table_x = |page_two: bool, float: TableFloat| {
+        let mut d = Document::from_text("First\nSecond\nAfter");
+        d.last_section.margin_left = 108.0;
+        d.last_section.margin_right = 36.0;
+        d.last_section.gutter = 10.0;
+        d.settings.mirror_margins = true;
+        if let Some(Block::Para(p)) = d.body.get_mut(1).map(Arc::make_mut) {
+            p.props.page_break_before = Some(page_two);
+        }
+        let mut t = wordcraft_doc::Table::new(1, 1, 100.0);
+        t.props.float = Some(float);
+        d.insert_block(StoryRef::Body, &Path::top(2), Block::Table(t)).unwrap();
+        let l = lay(&d);
+        let page = &l.pages[page_two as usize];
+        let x = page.items.iter().find_map(|it| match it {
+            Placed::Lines { story: StoryRef::Body, path, x, .. } if path.0.len() > 1 => Some(*x),
+            _ => None,
+        });
+        x.unwrap()
+    };
+    let outside = TableFloat { h_rel: Anchor::Margin, v_rel: Anchor::Paragraph, h_align: Some(FloatAlign::Outside), ..Default::default() };
+    let (odd, even) = (table_x(false, outside), table_x(true, outside));
+    assert!(odd > 576.0 - 100.0 - 0.01 && odd < 576.0, "odd page: at the right margin, text at {odd}");
+    assert!(even > 36.0 - 0.01 && even < 36.0 + 20.0, "even page: at the left margin, text at {even}");
+    let from_page = TableFloat { h_rel: Anchor::Page, v_rel: Anchor::Paragraph, x: 200.0, ..Default::default() };
+    let (odd, even) = (table_x(false, from_page), table_x(true, from_page));
+    assert!((odd - even).abs() < 0.01, "same place from the page edge: {odd} and {even}");
+}
+
 #[test]
 fn a_tall_footer_pushes_the_body_up() {
     // #453: an eight-line footer reaches far above the 72pt bottom margin.
diff --git a/crates/ui-egui/src/dialogs.rs b/crates/ui-egui/src/dialogs.rs
index d73a252cd..e86357d78 100644
--- a/crates/ui-egui/src/dialogs.rs
+++ b/crates/ui-egui/src/dialogs.rs
@@ -246,6 +246,8 @@ pub enum Dialog {
         left: f32,
         right: f32,
         landscape: bool,
+        /// Mirrored margins (the whole document's): left and right become inside and outside.
+        mirror: bool,
         /// Document grid: kind (0 none, 1 lines, 2 lines and characters, 3 snap to characters),
         /// lines per page and characters per line; `grid_was` as opened (applied only if changed).
         grid: (u8, u32, u32),
@@ -1175,6 +1177,7 @@ impl Dialog {
                     left: sp.margin_left / crate::options::unit().pt_per_unit(),
                     right: sp.margin_right / crate::options::unit().pt_per_unit(),
                     landscape: sp.landscape,
+                    mirror: app.session.doc.settings.mirror_margins,
                     grid,
                     grid_was: grid,
                     rtl: sp.rtl,
@@ -2118,7 +2121,7 @@ fn body(app: &mut WordApp, ui: &mut Ui, d: &mut Dialog) -> bool {
             }
             ok || cancel
         }
-        Dialog::PageSetup { top, bottom, left, right, landscape, rtl, grid, grid_was, paper, paper_was, paper_custom, message } => {
+        Dialog::PageSetup { top, bottom, left, right, landscape, mirror, rtl, grid, grid_was, paper, paper_was, paper_custom, message } => {
             ui.label(egui::RichText::new(tl!("Margins")).font(semibold(12.5)));
             egui::Grid::new("ps").num_columns(4).show(ui, |ui| {
                 ui.label(tl!("Top:"));
@@ -2128,9 +2131,9 @@ fn body(app: &mut WordApp, ui: &mut Ui, d: &mut Dialog) -> bool {
                     egui::DragValue::new(bottom).speed(3.6 / crate::options::unit().pt_per_unit()).measure(crate::options::unit()).max_decimals(2),
                 );
                 ui.end_row();
-                ui.label(tl!("Left:"));
+                ui.label(if *mirror { tl!("Inside:") } else { tl!("Left:") });
                 ui.add(egui::DragValue::new(left).speed(3.6 / crate::options::unit().pt_per_unit()).measure(crate::options::unit()).max_decimals(2));
-                ui.label(tl!("Right:"));
+                ui.label(if *mirror { tl!("Outside:") } else { tl!("Right:") });
                 ui.add(egui::DragValue::new(right).speed(3.6 / crate::options::unit().pt_per_unit()).measure(crate::options::unit()).max_decimals(2));
                 ui.end_row();
             });
@@ -2139,6 +2142,8 @@ fn body(app: &mut WordApp, ui: &mut Ui, d: &mut Dialog) -> bool {
                 ui.radio_value(landscape, false, tl!("Portrait"));
                 ui.radio_value(landscape, true, tl!("Landscape"));
             });
+            ui.label(egui::RichText::new(tl!("Pages")).font(semibold(12.5)));
+            ui.checkbox(mirror, tl!("Mirror margins"));
             page_paper_group(ui, paper, landscape, paper_custom);
             ui.label(egui::RichText::new(tl!("Document Grid")).font(semibold(12.5)));
             ui.horizontal_wrapped(|ui| {
@@ -2168,6 +2173,10 @@ fn body(app: &mut WordApp, ui: &mut Ui, d: &mut Dialog) -> bool {
                 let result = page_layout_commands(app, (*paper, *paper_was), *landscape, (*top, *bottom, *left, *right))
                     .map_err(|e| tl!(e).to_string())
                     .and_then(|mut commands| {
+                        // Mirror margins go with the margins (#1181).
+                        if let Some((_, v)) = commands.iter_mut().rev().find(|(id, _)| *id == "layout.margins") {
+                            v["mirror"] = json!(*mirror);
+                        }
                         if grid != grid_was {
                             let kind = ["none", "lines", "linesAndChars", "snapToChars"].get(grid.0 as usize).copied().unwrap_or("none");
                             let mut v = json!({"type": kind});
diff --git a/crates/ui-egui/src/i18n/bg.tsv b/crates/ui-egui/src/i18n/bg.tsv
index ce4a7100d..1cc29afa7 100644
--- a/crates/ui-egui/src/i18n/bg.tsv
+++ b/crates/ui-egui/src/i18n/bg.tsv
@@ -2566,3 +2566,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Възстановяване
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Огледални полета
diff --git a/crates/ui-egui/src/i18n/cs.tsv b/crates/ui-egui/src/i18n/cs.tsv
index 9aaed9095..9a19ab4fb 100644
--- a/crates/ui-egui/src/i18n/cs.tsv
+++ b/crates/ui-egui/src/i18n/cs.tsv
@@ -2570,3 +2570,6 @@ preview	Title	Ukázka
 
 # Backstage › Recover (#586)
 	Recover	Obnovit
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Zrcadlové okraje
diff --git a/crates/ui-egui/src/i18n/de.tsv b/crates/ui-egui/src/i18n/de.tsv
index 93e6b9e8e..c5858aa76 100644
--- a/crates/ui-egui/src/i18n/de.tsv
+++ b/crates/ui-egui/src/i18n/de.tsv
@@ -2178,3 +2178,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Wiederherstellen
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Gegenüberliegende Seiten
diff --git a/crates/ui-egui/src/i18n/es.tsv b/crates/ui-egui/src/i18n/es.tsv
index 910871ec3..782862571 100644
--- a/crates/ui-egui/src/i18n/es.tsv
+++ b/crates/ui-egui/src/i18n/es.tsv
@@ -2545,3 +2545,6 @@ preview	Title	Título
 
 # Backstage › Recover (#586)
 	Recover	Recuperar
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Márgenes simétricos
diff --git a/crates/ui-egui/src/i18n/et.tsv b/crates/ui-egui/src/i18n/et.tsv
index 4624c3f4d..a2e1c6e91 100644
--- a/crates/ui-egui/src/i18n/et.tsv
+++ b/crates/ui-egui/src/i18n/et.tsv
@@ -2213,3 +2213,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Taasta
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Peegelveerised
diff --git a/crates/ui-egui/src/i18n/fr.tsv b/crates/ui-egui/src/i18n/fr.tsv
index 2fd447dcb..238c27553 100644
--- a/crates/ui-egui/src/i18n/fr.tsv
+++ b/crates/ui-egui/src/i18n/fr.tsv
@@ -2186,3 +2186,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Récupérer
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Marges en vis-à-vis
diff --git a/crates/ui-egui/src/i18n/hu.tsv b/crates/ui-egui/src/i18n/hu.tsv
index 8bc2aec22..193aa9e97 100644
--- a/crates/ui-egui/src/i18n/hu.tsv
+++ b/crates/ui-egui/src/i18n/hu.tsv
@@ -2574,3 +2574,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Helyreállítás
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Tükrözött margók
diff --git a/crates/ui-egui/src/i18n/it.tsv b/crates/ui-egui/src/i18n/it.tsv
index 653b537c7..7de0a2539 100644
--- a/crates/ui-egui/src/i18n/it.tsv
+++ b/crates/ui-egui/src/i18n/it.tsv
@@ -2587,3 +2587,6 @@ preview	Title	Esempio
 	Use "an" before a vowel sound	Usa "an" davanti a un suono vocalico
 	➕ New comment	➕ Nuovo commento
 	📂  Browse…	📂  Sfoglia…
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Margini speculari
diff --git a/crates/ui-egui/src/i18n/ja.tsv b/crates/ui-egui/src/i18n/ja.tsv
index 287f9e6fd..fda529a91 100644
--- a/crates/ui-egui/src/i18n/ja.tsv
+++ b/crates/ui-egui/src/i18n/ja.tsv
@@ -2179,3 +2179,6 @@
 
 # Backstage › Recover (#586)
 	Recover	回復
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	見開きページ
diff --git a/crates/ui-egui/src/i18n/pl.tsv b/crates/ui-egui/src/i18n/pl.tsv
index ceb54c4a6..167b8994c 100644
--- a/crates/ui-egui/src/i18n/pl.tsv
+++ b/crates/ui-egui/src/i18n/pl.tsv
@@ -2568,3 +2568,6 @@ preview	Title	Tytuł
 
 # Backstage › Recover (#586)
 	Recover	Odzyskaj
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Marginesy lustrzane
diff --git a/crates/ui-egui/src/i18n/pt-br.tsv b/crates/ui-egui/src/i18n/pt-br.tsv
index 372ca915b..8011e2ac3 100644
--- a/crates/ui-egui/src/i18n/pt-br.tsv
+++ b/crates/ui-egui/src/i18n/pt-br.tsv
@@ -2191,3 +2191,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Recuperar
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Margens espelho
diff --git a/crates/ui-egui/src/i18n/ru.tsv b/crates/ui-egui/src/i18n/ru.tsv
index 7333adf54..223cb62da 100644
--- a/crates/ui-egui/src/i18n/ru.tsv
+++ b/crates/ui-egui/src/i18n/ru.tsv
@@ -2576,3 +2576,6 @@ preview	Title	Пример
 
 # Backstage › Recover (#586)
 	Recover	Восстановить
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Зеркальные поля
diff --git a/crates/ui-egui/src/i18n/sr-latn.tsv b/crates/ui-egui/src/i18n/sr-latn.tsv
index 9944d8cc8..e78bcc82e 100644
--- a/crates/ui-egui/src/i18n/sr-latn.tsv
+++ b/crates/ui-egui/src/i18n/sr-latn.tsv
@@ -2189,3 +2189,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Oporavi
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Preslikane margine
diff --git a/crates/ui-egui/src/i18n/sr.tsv b/crates/ui-egui/src/i18n/sr.tsv
index db5618148..06d11d5a4 100644
--- a/crates/ui-egui/src/i18n/sr.tsv
+++ b/crates/ui-egui/src/i18n/sr.tsv
@@ -2193,3 +2193,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Опорави
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Пресликане маргине
diff --git a/crates/ui-egui/src/i18n/tr.tsv b/crates/ui-egui/src/i18n/tr.tsv
index 18fb2c010..7124962c4 100644
--- a/crates/ui-egui/src/i18n/tr.tsv
+++ b/crates/ui-egui/src/i18n/tr.tsv
@@ -2575,3 +2575,6 @@ preview	Title	Örnek
 
 # Backstage › Recover (#586)
 	Recover	Kurtar
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Yansıtılmış kenar boşlukları
diff --git a/crates/ui-egui/src/i18n/uk.tsv b/crates/ui-egui/src/i18n/uk.tsv
index 4cc6dc3c6..e97733d8a 100644
--- a/crates/ui-egui/src/i18n/uk.tsv
+++ b/crates/ui-egui/src/i18n/uk.tsv
@@ -2191,3 +2191,6 @@
 
 # Backstage › Recover (#586)
 	Recover	Відновити
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Дзеркальні поля
diff --git a/crates/ui-egui/src/i18n/vi.tsv b/crates/ui-egui/src/i18n/vi.tsv
index 68e05e217..d2a8f345a 100644
--- a/crates/ui-egui/src/i18n/vi.tsv
+++ b/crates/ui-egui/src/i18n/vi.tsv
@@ -2606,3 +2606,6 @@
 	Delete Bookmark	Xóa dấu trang
 	Hidden bookmarks	Dấu trang ẩn
 	Sort by:	Sắp xếp theo:
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	Lề đối xứng
diff --git a/crates/ui-egui/src/i18n/zh-hans.tsv b/crates/ui-egui/src/i18n/zh-hans.tsv
index d41d57836..0e45b48e7 100644
--- a/crates/ui-egui/src/i18n/zh-hans.tsv
+++ b/crates/ui-egui/src/i18n/zh-hans.tsv
@@ -2191,3 +2191,6 @@
 
 # Backstage › Recover (#586)
 	Recover	恢复
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	对称页边距
diff --git a/crates/ui-egui/src/i18n/zh-hant.tsv b/crates/ui-egui/src/i18n/zh-hant.tsv
index 0141e7fad..eb7c728c9 100644
--- a/crates/ui-egui/src/i18n/zh-hant.tsv
+++ b/crates/ui-egui/src/i18n/zh-hant.tsv
@@ -2180,3 +2180,6 @@
 
 # Backstage › Recover (#586)
 	Recover	復原
+
+# Page Setup › Mirror margins (#1239)
+	Mirror margins	左右對稱邊界
diff --git a/crates/ui-egui/src/ribbon.rs b/crates/ui-egui/src/ribbon.rs
index ab2219a24..047f5c687 100644
--- a/crates/ui-egui/src/ribbon.rs
+++ b/crates/ui-egui/src/ribbon.rs
@@ -1354,7 +1354,9 @@ fn margins_items(ui: &mut Ui, app: &mut WordApp) {
         ("Mirrored", "mirrored"),
         ("Office 2003 Default", "office2003"),
     ] {
-        mi_check(ui, app, l, current == Some(k), "layout.margins", json!({"preset": k}));
+        // Mirrored margins come from the document as well as from the preset (#1181).
+        let on = current == Some(k) || (k == "mirrored" && app.session.doc.settings.mirror_margins);
+        mi_check(ui, app, l, on, "layout.margins", json!({"preset": k}));
     }
     mi(ui, app, "Custom Margins…", "ui.dialog", json!({"name": "pageSetup"}));
 }
diff --git a/docs/layout-parity.md b/docs/layout-parity.md
index 29eb241e2..82b41985b 100644
--- a/docs/layout-parity.md
+++ b/docs/layout-parity.md
@@ -1,6 +1,6 @@
 # Layout and pagination parity with Microsoft Word
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** trivial (STYLEREF running headers per page, #775; previously trivial: PAGEREF in headers and footers shows its bookmark's page, #1477; previously trivial: a paragraph continued into the next column or page wraps around that column's shapes, #1374; previously trivial: PAGE fields in a paragraph split across pages show the page they are on, #1352; previously trivial: symbol-font text drawn as Unicode symbols, #776; previously trivial: large-table scrolling measured and fixed, #811; previously trivial: text boxes use their own margins; Resize shape to fit text never cuts text, #743; previously trivial: complex-script shaping and Myanmar line breaking, #604; previously trivial: body page totals, table-cell footnotes and bookmark link pages fixed, #450 #451 #455; previously major: first version; line breaking, pagination and object placement checked against Word's behaviour from the layout source on origin/main) · **Target:** Microsoft Word (Microsoft 365) for Mac 16.113.4
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-14 · **Change:** trivial (floats aligned inside/outside or placed in the inside/outside margin swap sides on even pages; page-relative floats no longer move with mirrored text, #1181; previously trivial: STYLEREF running headers per page, #775; previously trivial: PAGEREF in headers and footers shows its bookmark's page, #1477; previously trivial: a paragraph continued into the next column or page wraps around that column's shapes, #1374; previously trivial: PAGE fields in a paragraph split across pages show the page they are on, #1352; previously trivial: symbol-font text drawn as Unicode symbols, #776; previously trivial: large-table scrolling measured and fixed, #811; previously trivial: text boxes use their own margins; Resize shape to fit text never cuts text, #743; previously trivial: complex-script shaping and Myanmar line breaking, #604; previously trivial: body page totals, table-cell footnotes and bookmark link pages fixed, #450 #451 #455; previously major: first version; line breaking, pagination and object placement checked against Word's behaviour from the layout source on origin/main) · **Target:** Microsoft Word (Microsoft 365) for Mac 16.113.4
 
 A document only "opens correctly" if its pages break where Word breaks them: the same lines, the
 same page count, footnotes and pictures on the same pages. This checklist covers line breaking,
@@ -53,7 +53,7 @@ font can't match Word's metrics.
 | Page borders (from page edge or text), page colour, watermark | ✅ | | — |
 | Line numbers (restart per page/section, count by) | ✅ | | — |
 | Vertical page alignment | ✅ | | — |
-| Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins (even pages put the inside margin and gutter on the right, #452; page-relative floats move with the text); book fold missing | 2–3 |
+| Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins (even pages put the inside margin and gutter on the right, #452; page-relative floats stay put, and inside/outside alignment and margins follow the page side, #1181); book fold missing | 2–3 |
 | Vertical text (`tbRl`) in sections and text boxes; cell text direction | ✅ | cell text direction (#245); text-box text direction (#369); vertical sections (`tbRl`/`btLr`, #491): the page's text area turned, lines top to bottom stacking right to left, ideographs, kana and Hangul upright, Latin on its side, caret and clicks through the turn. Missing: OpenType `vert` alternates (punctuation is moved, not substituted), arrow keys along vertical lines, upright pictures take turned room | 2–4 |
 | Gutter, mirror margins, book fold, 2 pages per sheet | 🟡 | gutter and mirror margins; book fold missing | 2–3 |
 | Document grid (`w:docGrid`, lines per page, characters per line) | 🟡 | #391, #401: line grid snaps line heights to whole pitches (text centred in them; `w:snapToGrid` off opts a paragraph out); character grid puts East Asian characters on the character pitch (`linesAndChars`) or all text (`snapToChars`), Latin text proportional; View › Gridlines draws it. Not yet: run-level `w:snapToGrid`, grid in headers/footers, paragraph spacing in grid lines, Word's exact glyph placement in a cell | 1–2 |
@@ -158,6 +158,7 @@ No overall parity estimate changes from these probes.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-13 | trivial | Floats and floating tables aligned inside/outside, or placed in the inside/outside margin, swap sides on even pages; with mirrored margins, page-relative floats keep their place and left/right margin areas are each page's own (#1181) |
 | 2026-10-13 | trivial | PAGEREF in headers and footers shows its bookmark's page (#1477) |
 | 2026-10-13 | trivial | A shape or picture dragged into another column anchors there, so the text in that column wraps around it (#884) |
 | 2026-10-13 | trivial | On a page with footnotes, a paragraph that ends there keeps its space after above the footnote separator; if it doesn't fit, its last line (and, with widow control, one more) goes to the next page with the note. Pages without notes are unchanged (#1116) |