diff --git a/static/mobile/js/utils.js b/static/mobile/js/utils.js
index 92d6c8064..25e8a4017 100644
--- a/static/mobile/js/utils.js
+++ b/static/mobile/js/utils.js
@@ -6,11 +6,15 @@ const parseDuration = function(string) {
 };
 
 const formatDuration = function(seconds) {
+    if (isString(seconds)) {
+        seconds = parseFloat(seconds)
+    }
+    seconds = seconds.toFixed(3)
     var parts = [
         parseInt(seconds / 86400),
         parseInt(seconds % 86400 / 3600),
         parseInt(seconds % 3600 / 60),
-        s = parseInt(seconds % 60)
+        parseInt(seconds % 60)
     ]
     return parts.map(p => { return p.toString().padStart(2, '0')}).join(':')
 }