diff --git a/webapp/src/components/common/Matrix/hooks/useMatrix/index.ts b/webapp/src/components/common/Matrix/hooks/useMatrix/index.ts
index 286b732405..6558e764e8 100644
--- a/webapp/src/components/common/Matrix/hooks/useMatrix/index.ts
+++ b/webapp/src/components/common/Matrix/hooks/useMatrix/index.ts
@@ -320,5 +320,9 @@ export function useMatrix(
     canUndo: canUndoChanges,
     canRedo,
     reload: fetchMatrix,
+    // Use the matrix index 'steps' field to determine the number of rows
+    // This ensures consistent row display (8760 for hourly, 365 for daily/weekly)
+    // rather than using data.length which can vary for Binding Constraints (8784/366)
+    rowCount: index?.steps,
   };
 }
diff --git a/webapp/src/components/common/Matrix/index.tsx b/webapp/src/components/common/Matrix/index.tsx
index 1316d2d7f2..4bb07202dd 100644
--- a/webapp/src/components/common/Matrix/index.tsx
+++ b/webapp/src/components/common/Matrix/index.tsx
@@ -83,6 +83,7 @@ function Matrix({
     canUndo,
     canRedo,
     reload,
+    rowCount,
   } = useMatrix(
     study.id,
     url,
@@ -136,7 +137,7 @@ function Matrix({
           data={data}
           aggregates={aggregates}
           columns={columns}
-          rows={data.length}
+          rows={rowCount ?? data.length}
           rowHeaders={customRowHeaders}
           dateTime={dateTime}
           onCellEdit={handleCellEdit}