diff --git a/lib/runCall.js b/lib/runCall.js
index f7084fff64..ceafafaf21 100644
--- a/lib/runCall.js
+++ b/lib/runCall.js
@@ -159,14 +159,9 @@ module.exports = function (opts, cb) {
         // fee for size of the return value
         var totalGas = results.gasUsed
         if (!results.runState.vmError) {
-          var returnFee = results.return.length * fees.createDataGas.v
+          var returnFee = new BN(results.return.length * fees.createDataGas.v)
 
-          // avoid BN assertion failure when returnFee is greater than 0x4000000
-          if (returnFee > gasLimit.toNumber()) {
-            returnFee = gasLimit.toNumber() + 1
-          }
-
-          totalGas = totalGas.addn(returnFee)
+          totalGas = totalGas.add(returnFee)
         }
         // if not enough gas
         if (totalGas.lte(gasLimit) && results.return.length <= 24576) {