diff --git a/judge/views/course.py b/judge/views/course.py
index fb31aa7..8ab5c92 100644
--- a/judge/views/course.py
+++ b/judge/views/course.py
@@ -60,7 +60,7 @@ def calculate_lessons_progress(profile, lessons):
     res["total"] = {
         "achieved_points": total_achieved_points,
         "total_points": total_points,
-        "percentage": total_achieved_points / total_points * 100,
+        "percentage": total_achieved_points / total_points * 100 if total_points else 0,
     }
     return res