diff --git a/src/cartsnitch_api/middleware/rate_limit.py b/src/cartsnitch_api/middleware/rate_limit.py
index d453ab7..22552ec 100644
--- a/src/cartsnitch_api/middleware/rate_limit.py
+++ b/src/cartsnitch_api/middleware/rate_limit.py
@@ -84,7 +84,7 @@ class RedisSlidingWindow:
             if current_count >= self.max_requests:
                 oldest = await self.redis.zrange(key, 0, 0, withscores=True)
                 if oldest:
-                    retry_after = int((oldest[0][1] - cutoff) / 1000) + 1
+                    retry_after = int((float(oldest[0][1]) - cutoff) / 1000) + 1
                 else:
                     retry_after = self.window_seconds
                 return False, 0, retry_after