diff --git a/src/app/(app)/invoicing/page.tsx b/src/app/(app)/invoicing/page.tsx
index 75e71b8..af07ce5 100644
--- a/src/app/(app)/invoicing/page.tsx
+++ b/src/app/(app)/invoicing/page.tsx
@@ -23,6 +23,7 @@ import {
   buildDeliveryNotePrintGroups,
   buildTodayUnprintedDeliveryNoteGroups,
   buildQbInvoicePayload,
+  billableRows,
   nameSimilarity,
   buildOrderInvoiceCards,
   buildRecentInvoiceRange,
@@ -2048,6 +2049,20 @@ export default function InvoicingPage() {
           toast.error("Pick at least one item before sending to QuickBooks.");
           return false;
         }
+        // Task 6 of the non-invoiceable-order-extras plan. `rows.length`
+        // above counts excluded rows, which ride along for the n8n
+        // status flip but never bill. If every row in the group is
+        // excluded the payload's `items` array would be empty and
+        // QuickBooks would receive a zero-line invoice.
+        //
+        // Both live modals disable submit on this case, so this is
+        // defence-in-depth for the callers that bypass them: the
+        // (currently unrendered) bulk modal and any legacy call that
+        // passes `overrides: undefined` and falls back to every row.
+        if (billableRows(rows).length === 0) {
+          toast.error("This order has no billable lines.");
+          return false;
+        }
         const first = rows[0];
         const similarity = nameSimilarity(customer.name, first.companyName ?? "");
         if (similarity < 0.35) {