diff --git a/src/coupon/index.js b/src/coupon/index.js
index 3b10cd5f1..947ac1487 100644
--- a/src/coupon/index.js
+++ b/src/coupon/index.js
@@ -10,7 +10,7 @@ function formatTimeStamp(timeStamp) {
   if (timeStamp < 10 ** 12) {
     return timeStamp * 1000;
   }
-  return timeStamp;
+  return +timeStamp;
 }
 
 function getDate(timeStamp) {