diff --git a/js/planner.js b/js/planner.js
index 4ac4237..c565196 100644
--- a/js/planner.js
+++ b/js/planner.js
@@ -81,7 +81,7 @@ function copyPlan(id) {
     const copy = {
         ...JSON.parse(JSON.stringify(orig)),
         id:        crypto.randomUUID(),
-        name:      orig.name + ' (Kopie)',
+        name:      uniquePlanName(orig.name + ' (Kopie)'),
         createdAt: Date.now(),
         updatedAt: Date.now()
     };