diff --git a/src/routes/invoices.$invoiceId.tsx b/src/routes/invoices.$invoiceId.tsx
index 357f412..95fab9b 100644
--- a/src/routes/invoices.$invoiceId.tsx
+++ b/src/routes/invoices.$invoiceId.tsx
@@ -317,10 +317,16 @@ function InvoiceDetail() {
   };
 
   const deleteInvoice = async () => {
-    if (!confirm("Delete this draft invoice and unbill its time/expenses?")) return;
+    const msg = isDraft
+      ? "Delete this draft invoice and unbill its time/expenses?"
+      : `Permanently delete invoice ${invoice.invoice_number}? This will remove all payments and unbill its time/expenses. This cannot be undone.`;
+    if (!confirm(msg)) return;
     // Unlink time/expenses
     await supabase.from("time_entries").update({ invoice_id: null }).eq("invoice_id", invoiceId);
     await supabase.from("expenses").update({ invoice_id: null }).eq("invoice_id", invoiceId);
+    // Remove payments first (no cascade guarantee)
+    await supabase.from("invoice_payments").delete().eq("invoice_id", invoiceId);
+    await supabase.from("invoice_line_items").delete().eq("invoice_id", invoiceId);
     const { error } = await supabase.from("invoices").delete().eq("id", invoiceId);
     if (error) return toast.error(error.message);
     toast.success("Invoice deleted");