diff --git a/server/src/functions/update_average_punctuality/lambda_function.py b/server/src/functions/update_average_punctuality/lambda_function.py
index ee507ef..8ee2d32 100644
--- a/server/src/functions/update_average_punctuality/lambda_function.py
+++ b/server/src/functions/update_average_punctuality/lambda_function.py
@@ -62,7 +62,8 @@ def update_punctuality_by_timestamp(timestamp, punctualities):
     if not punctualities:
         return
 
-    avg_punctuality = sum(punctualities) / len(punctualities)
+    avg_punctuality = Decimal(str(sum(punctualities) / len(punctualities)))  # Ensure Decimal type
+    timestamp = Decimal(str(timestamp))  # Ensure Decimal type
 
     # Insert or update record in DynamoDB
     table_timestamp.put_item(