diff --git a/scipost_django/common/converters.py b/scipost_django/common/converters.py
index 76a8a94c268bb35644fa86a89147aba5d4d00362..5dddfd086ab6e44f353608b8efb7b2510a34ea1a 100644
--- a/scipost_django/common/converters.py
+++ b/scipost_django/common/converters.py
@@ -16,7 +16,7 @@ class FourDigitYearConverter:
         return int(value)
 
     def to_url(self, value):
-        return '%04d' % value
+        return '%04d' % int(value)
 
 
 class TwoDigitMonthConverter: