diff --git a/crates/xlsx/src/pivot.rs b/crates/xlsx/src/pivot.rs
index 609ae530e..fd00d0234 100644
--- a/crates/xlsx/src/pivot.rs
+++ b/crates/xlsx/src/pivot.rs
@@ -816,10 +816,12 @@ fn table_xml(pt: &PivotTable, idx: usize, cache_id: u32, c: &Cache, fmt_id: &dyn
     if !pt.show_headers {
         s.push_str(" showHeaders=\"0\"");
     }
-    if !pt.grand_totals_rows {
+    // `rowGrandTotals` is the grand total row below the report (Excel's "On for Columns"),
+    // `colGrandTotals` the grand total column at its right ("On for Rows").
+    if !pt.grand_totals_cols {
         s.push_str(" rowGrandTotals=\"0\"");
     }
-    if !pt.grand_totals_cols {
+    if !pt.grand_totals_rows {
         s.push_str(" colGrandTotals=\"0\"");
     }
     s.push_str(" multipleFieldFilters=\"0\">");
@@ -1262,8 +1264,8 @@ fn read_table(cx: &mut Ctx<'_>, x: &El, cache: &CacheIn, id: u32) -> Option<Pivo
         pt.subtotals = f.flag("defaultSubtotal", true);
         pt.subtotals_top = f.flag("subtotalTop", true);
     }
-    pt.grand_totals_rows = x.flag("rowGrandTotals", true);
-    pt.grand_totals_cols = x.flag("colGrandTotals", true);
+    pt.grand_totals_rows = x.flag("colGrandTotals", true);
+    pt.grand_totals_cols = x.flag("rowGrandTotals", true);
     pt.show_headers = x.flag("showHeaders", true);
     pt.style = x.child("pivotTableStyleInfo").and_then(|s| s.attr("name")).unwrap_or("").to_string();
     if x.child("calculatedItems").is_some() || x.path(&["filters", "filter"]).is_some() {
diff --git a/crates/xlsx/src/tests/pivot_tests.rs b/crates/xlsx/src/tests/pivot_tests.rs
index 99a15d6e7..31945c688 100644
--- a/crates/xlsx/src/tests/pivot_tests.rs
+++ b/crates/xlsx/src/tests/pivot_tests.rs
@@ -355,6 +355,10 @@ fn pivot_xml_details() {
     let t2 = String::from_utf8(parts.get("xl/pivotTables/pivotTable2.xml").unwrap().clone()).unwrap();
     assert!(t2.contains("pivotShowAs=\"rankDescending\""));
     assert!(t2.contains("showDataAs=\"runTotal\""));
+    // Pivot 1 has no Grand Total column (`colGrandTotals`), pivot 2 no Grand Total row
+    // (`rowGrandTotals`).
+    assert!(t1.contains(" colGrandTotals=\"0\"") && !t1.contains("rowGrandTotals"), "{t1}");
+    assert!(t2.contains(" rowGrandTotals=\"0\"") && !t2.contains("colGrandTotals"), "{t2}");
     // The custom value format is registered in the styles part.
     let styles = String::from_utf8(parts.get("xl/styles.xml").unwrap().clone()).unwrap();
     assert!(styles.contains("formatCode=\"0.0&quot; u&quot;\""));
@@ -579,6 +583,25 @@ fn values_ahead_of_column_fields_read_last() {
     assert_eq!(pt.values_position, None);
 }
 
+// As Excel saves them: `rowGrandTotals="0"` drops the Grand Total row under the report (leaving
+// Excel's "On for Rows Only"), `colGrandTotals="0"` the Grand Total column at its right ("On for
+// Columns Only"). LibreOffice's Pivot2_Row_Subtotals.xlsx (`rowGrandTotals="0"`) shows no Grand
+// Total row; ClosedXML's TemplateWithTableSourcePivotTables.xlsx pivotTable5 (`colGrandTotals="0"`,
+// row and column fields) shows a Grand Total row and no Grand Total column.
+#[test]
+fn grand_totals_read_in_excel_direction() {
+    let table = |attr: &str| {
+        format!(
+            r#"<pivotTableDefinition name="GT" cacheId="1" {attr}><location ref="C1:F4"/><pivotFields><pivotField axis="axisRow"><items><item x="0"/><item x="1"/><item t="default"/></items></pivotField><pivotField dataField="1"/></pivotFields><rowFields><field x="0"/></rowFields><dataFields><dataField name="Sum of V" fld="1"/></dataFields></pivotTableDefinition>"#
+        )
+    };
+    for (attr, rows, cols) in [("rowGrandTotals=\"0\"", true, false), ("colGrandTotals=\"0\"", false, true), ("", true, true)] {
+        let (wb, _) = read_xlsx(&with_pivot(&table(attr), Some(GOOD_CACHE))).unwrap();
+        let pt = &wb.sheet(0).unwrap().pivots[0];
+        assert_eq!((pt.grand_totals_rows, pt.grand_totals_cols), (rows, cols), "{attr}");
+    }
+}
+
 #[test]
 fn data_on_rows_with_one_value_field_reads_without_warning() {
     let table = r#"<pivotTableDefinition name="OneValue" cacheId="1" dataOnRows="1"><location ref="C1:D4"/><pivotFields><pivotField axis="axisRow"><items><item x="0"/><item x="1"/><item t="default"/></items></pivotField><pivotField dataField="1"/></pivotFields><rowFields><field x="0"/></rowFields><dataFields><dataField name="Total" fld="1"/></dataFields></pivotTableDefinition>"#;
diff --git a/docs/file-format-parity.md b/docs/file-format-parity.md
index 158149fb3..61df43deb 100644
--- a/docs/file-format-parity.md
+++ b/docs/file-format-parity.md
@@ -1,6 +1,6 @@
 # File-format parity
 
-> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-14 · **Change:** trivial (formulas over Excel's 8,192 characters, and `%` or call chains past the nesting limit, are parse errors instead of stack overflows when a file is opened; previously trivial: XLSX chart sheets are kept on save (#727)) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
+> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-18 · **Change:** trivial (XLSX PivotTables read and write `rowGrandTotals`/`colGrandTotals` the way Excel does, so a table saved with only one grand total opens with the right one; previously trivial: formulas over Excel's 8,192 characters, and `%` or call chains past the nesting limit, are parse errors instead of stack overflows when a file is opened) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
 
 Every format Excel opens or saves, with GridCraft's read and write support, fidelity and tests.
 Part of [target-app-parity.md](target-app-parity.md). **File formats: ~50% ready, 80–120 h**
@@ -85,6 +85,7 @@ refresh. Counted under features (Get & Transform, ~10% ready), not here.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-18 | trivial | XLSX PivotTables: `rowGrandTotals` is the Grand Total row and `colGrandTotals` the Grand Total column. Both were read and written the other way round, which a GridCraft round trip hid, so an Excel file with only one grand total opened showing the other |
 | 2026-10-14 | trivial | Formula parser: text longer than Excel's 8,192 characters, and postfix chains (`1%%%…`, `f(1)(1)…`) past the 256-level nesting limit, are parse errors (the cell keeps its formula text and cached value) instead of trees deep enough to overflow the stack when a hostile file is opened, saved or dropped |
 | 2026-10-12 | trivial | XLSX chart sheets are kept on save (#727) |
 | 2026-10-12 | trivial | CSV and TSV export is capped at 512 MiB and refuses a larger used range with an error (#528) |