diff --git a/crates/ui-egui/src/formula_bar.rs b/crates/ui-egui/src/formula_bar.rs
index 7f1ad87fc..848ba5458 100644
--- a/crates/ui-egui/src/formula_bar.rs
+++ b/crates/ui-egui/src/formula_bar.rs
@@ -279,7 +279,13 @@ pub fn editor_widget(app: &mut SheetApp, ui: &mut egui::Ui, id: egui::Id, font:
         job.wrap.max_width = if multiline { wrap_width } else { f32::INFINITY };
         ui.fonts_mut(|f| f.layout_job(job))
     };
-    let edit = if multiline || ed.text.contains('\n') { TextEdit::multiline(&mut ed.text) } else { TextEdit::singleline(&mut ed.text) };
+    // The in-cell editor is as tall as its lines (a multiline field reserves four rows).
+    let in_cell = id == egui::Id::new("gridcraft.cell_editor");
+    let edit = if multiline || ed.text.contains('\n') {
+        TextEdit::multiline(&mut ed.text).desired_rows(if in_cell { 1 } else { 4 })
+    } else {
+        TextEdit::singleline(&mut ed.text)
+    };
     let mut output = edit
         .id(id)
         .frame(egui::Frame::NONE)
diff --git a/crates/ui-egui/src/grid.rs b/crates/ui-egui/src/grid.rs
index 90a39cb06..6cd49691c 100644
--- a/crates/ui-egui/src/grid.rs
+++ b/crates/ui-egui/src/grid.rs
@@ -2707,10 +2707,18 @@ fn in_cell_editor(app: &mut SheetApp, ui: &mut egui::Ui, geo: &Geo, sh: &Sheet,
     let st = wb.styles.get(sh.style_id(cell)).clone();
     let size = st.font.size * 96.0 / 72.0 * geo.z;
     let font = FontId::new(size, theme::cell_family(&st.font.name, st.font.bold, st.font.italic));
-    let text_w = ui.painter().layout_no_wrap(ed.text.clone(), font.clone(), Color32::BLACK).size().x;
     let lines = ed.text.lines().count().max(1) as f32 + if ed.text.ends_with('\n') { 1.0 } else { 0.0 };
-    let w = (text_w + 14.0).max(rect.width()).min(geo.cells.right() - rect.left());
-    let h = (size * 1.3 * lines + 4.0).max(rect.height());
+    // Wrap Text: the editor keeps the column's width and wraps, growing down as Excel's does.
+    // Otherwise it widens to the text's one-line width.
+    let wrap = st.align.wrap;
+    let (w, h) = if wrap {
+        // The field's own margins (4 px a side) and the 2 px inset leave this much for the text.
+        let wrapped = ui.painter().layout(ed.text.clone(), font.clone(), Color32::BLACK, (rect.width() - 12.0).max(1.0));
+        (rect.width(), (wrapped.size().y.max(size * 1.3 * lines) + 4.0).max(rect.height()))
+    } else {
+        let text_w = ui.painter().layout_no_wrap(ed.text.clone(), font.clone(), Color32::BLACK).size().x;
+        ((text_w + 14.0).max(rect.width()).min(geo.cells.right() - rect.left()), (size * 1.3 * lines + 4.0).max(rect.height()))
+    };
     // Grows to the left on a right-to-left sheet.
     let erect = geo.mirror_rect(Rect::from_min_size(rect.min, vec2(w, h)));
     let fill = match st.fill.pattern {
@@ -2729,7 +2737,7 @@ fn in_cell_editor(app: &mut SheetApp, ui: &mut egui::Ui, geo: &Geo, sh: &Sheet,
     let id = egui::Id::new("gridcraft.cell_editor");
     let mut child = ui.new_child(egui::UiBuilder::new().max_rect(erect.shrink2(vec2(2.0, 1.0))));
     child.set_clip_rect(clip);
-    crate::formula_bar::editor_widget(app, &mut child, id, font, false, erect.width() - 4.0);
+    crate::formula_bar::editor_widget(app, &mut child, id, font, wrap, erect.width() - 4.0);
 }
 
 /// Test the popup itself, not whether the pointer is over any part of the app.
diff --git a/crates/ui-egui/tests/in_cell_editor_wrap.rs b/crates/ui-egui/tests/in_cell_editor_wrap.rs
new file mode 100644
index 000000000..7ebbf79ea
--- /dev/null
+++ b/crates/ui-egui/tests/in_cell_editor_wrap.rs
@@ -0,0 +1,59 @@
+//! The in-cell editor of a Wrap Text cell keeps the column's width and wraps, growing down, as
+//! Excel's does; it used to widen to one long line.
+use egui::{Context, Id, RawInput, Rect, pos2, vec2};
+use gridcraft_engine::Session;
+use gridcraft_ui_egui::SheetApp;
+use serde_json::json;
+
+const TEXT: &str = "Since the 1960s, NASA has left hardware across the solar system, on the Moon, on Mars, and in deep space.";
+
+/// Runs a few frames of the app in a 1200 × 800 window.
+fn frames(ctx: &Context, app: &mut SheetApp) {
+    for _ in 0..4 {
+        let mut output =
+            ctx.run_ui(RawInput { screen_rect: Some(Rect::from_min_size(pos2(0.0, 0.0), vec2(1200.0, 800.0))), ..Default::default() }, |ui| {
+                let ctx = ui.ctx().clone();
+                app.logic(&ctx);
+                app.ui(ui);
+            });
+        output.textures_delta.clear();
+    }
+}
+
+/// The editor's text field rect while A1 (narrow, wrap on or off) is edited with [`TEXT`].
+fn editor_rect(wrap: bool) -> Rect {
+    let ctx = Context::default();
+    let mut session = Session::new();
+    session.new_workbook();
+    session.execute("home.columnWidth", json!({"cols": "A:A", "chars": 12})).unwrap();
+    session.execute("home.wrapText", json!({"range": "A1", "on": wrap})).unwrap();
+    let mut app = SheetApp::new(session, Default::default());
+    frames(&ctx, &mut app);
+    app.begin_edit(Some(TEXT.into()), false);
+    frames(&ctx, &mut app);
+    ctx.read_response(Id::new("gridcraft.cell_editor")).expect("the in-cell editor is shown").rect
+}
+
+#[test]
+fn a_wrap_text_cell_edits_wrapped_at_the_column_width() {
+    let wrapped = editor_rect(true);
+    let one_line = editor_rect(false);
+    assert!(one_line.width() > 400.0, "without Wrap Text the editor widens to the text: {one_line:?}");
+    assert!(wrapped.width() < 120.0, "with Wrap Text the editor keeps the column's width: {wrapped:?}");
+    assert!(wrapped.height() > 4.0 * one_line.height(), "and grows down to show every line: {wrapped:?} vs {one_line:?}");
+}
+
+/// A short Wrap Text edit stays one line tall: the field doesn't reserve rows over the cells below.
+#[test]
+fn a_short_wrap_text_edit_stays_one_line_tall() {
+    let ctx = Context::default();
+    let mut session = Session::new();
+    session.new_workbook();
+    session.execute("home.wrapText", json!({"range": "A1", "on": true})).unwrap();
+    let mut app = SheetApp::new(session, Default::default());
+    frames(&ctx, &mut app);
+    app.begin_edit(Some("short".into()), false);
+    frames(&ctx, &mut app);
+    let field = ctx.read_response(Id::new("gridcraft.cell_editor")).expect("the in-cell editor is shown").rect;
+    assert!(field.height() < 30.0, "a one-line edit doesn't reach over the rows below: {field:?}");
+}