diff --git a/firka/lib/core/average_helper.dart b/firka/lib/core/average_helper.dart
index b255c39..98c2e6f 100644
--- a/firka/lib/core/average_helper.dart
+++ b/firka/lib/core/average_helper.dart
@@ -1,7 +1,7 @@
 import 'package:kreta_api/kreta_api.dart';
 
 bool _isPercentageGrade(Grade grade) {
-  final name = grade.valueType.name.toLowerCase();
+  final name = grade.valueType.name?.toLowerCase() ?? '';
   return name.contains('szazalek') || name.contains('percent');
 }
 
diff --git a/firka/lib/data/widget.dart b/firka/lib/data/widget.dart
index 20dbe03..dd7be4d 100644
--- a/firka/lib/data/widget.dart
+++ b/firka/lib/data/widget.dart
@@ -322,7 +322,7 @@ class WidgetCacheHelper {
     var sum = 0.0;
 
     for (var grade in grades) {
-      final name = grade.valueType.name.toLowerCase();
+      final name = grade.valueType.name?.toLowerCase() ?? '';
       final isPercentage =
           name.contains('szazalek') || name.contains('percent');
       if (isPercentage) continue;
diff --git a/firka/lib/ui/phone/widgets/grade_chart.dart b/firka/lib/ui/phone/widgets/grade_chart.dart
index 78bb8fe..94c1eb3 100644
--- a/firka/lib/ui/phone/widgets/grade_chart.dart
+++ b/firka/lib/ui/phone/widgets/grade_chart.dart
@@ -33,7 +33,7 @@ class _GradeChartState extends State<GradeChart> {
     double totalWeight = 0;
     for (final g in grades) {
       if (g.subject.uid != subjectUid) continue;
-      final name = g.valueType.name.toLowerCase();
+      final name = g.valueType.name?.toLowerCase() ?? '';
       final isPercentage =
           name.contains('szazalek') || name.contains('percent');
       if (isPercentage) continue;
diff --git a/firka_common/lib/ui/components/grade_helpers.dart b/firka_common/lib/ui/components/grade_helpers.dart
index d0b98f6..4f202b4 100644
--- a/firka_common/lib/ui/components/grade_helpers.dart
+++ b/firka_common/lib/ui/components/grade_helpers.dart
@@ -86,7 +86,7 @@ extension GradeListExtension on List<Grade> {
 
     for (var grade in this) {
       if (grade.subject.uid == subject.uid) {
-        final name = grade.valueType.name.toLowerCase();
+        final name = grade.valueType.name?.toLowerCase() ?? '';
         final isPercentage =
             name.contains('szazalek') || name.contains('percent');