diff --git a/src/mappers/har.js b/src/mappers/har.js
index <HASH>..<HASH> 100644
--- a/src/mappers/har.js
+++ b/src/mappers/har.js
@@ -190,6 +190,6 @@ function getOptionalDuration (start, end) {
         return -1;
     }
 
-    return parseInt(end) - parseInt(start);
+    return end - start;
 }
Remove unnecessary calls to parseInt.