diff --git a/apps/frontend/src/components/cards/EvaluationInfo.vue b/apps/frontend/src/components/cards/EvaluationInfo.vue
index 12bc92df52..420b93cc6c 100644
--- a/apps/frontend/src/components/cards/EvaluationInfo.vue
+++ b/apps/frontend/src/components/cards/EvaluationInfo.vue
@@ -102,7 +102,8 @@ export default class EvaluationInfo extends Vue {
   }
 
   get duration(): string | undefined {
-    return _.get(this.file_object, 'evaluation.data.statistics.duration');
+    const duration = _.get(this.file_object, 'evaluation.data.statistics.duration');
+    return duration === null || duration == undefined ? undefined : duration.toString();
   }
 
   get evaluation(): IEvaluation | undefined {