diff --git a/src/pages/RoomsPage.tsx b/src/pages/RoomsPage.tsx
index 337ad06..572e036 100644
--- a/src/pages/RoomsPage.tsx
+++ b/src/pages/RoomsPage.tsx
@@ -208,6 +208,7 @@ export function RoomsPage() {
key={editingRoom?.id ?? 'new'}
open={modalOpen}
room={editingRoom}
+ existingNumbers={rooms.map(r => r.number)}
onClose={() => { setModalOpen(false); setSaveError(null) }}
onSave={handleSave}
categories={categories}