diff --git a/js/directives.js b/js/directives.js
index 586a1ac31..fac694ddb 100644
--- a/js/directives.js
+++ b/js/directives.js
@@ -40,12 +40,12 @@ angular.module('copayApp.directives')
   .directive('enoughAmount', ['$rootScope',
     function($rootScope) {
       var bitcore = require('bitcore');
-      var feeSat = bitcore.TransactionBuilder.FEE_PER_1000B_SAT;
+      var feeSat = Number(bitcore.TransactionBuilder.FEE_PER_1000B_SAT);
       return {
         require: 'ngModel',
         link: function(scope, element, attrs, ctrl) {
           var val = function(value) {
-            var availableBalanceNum = ($rootScope.availableBalance * config.unitToSatoshi).toFixed(0);
+            var availableBalanceNum = Number(($rootScope.availableBalance * config.unitToSatoshi).toFixed(0));
             var vNum = Number((value * config.unitToSatoshi).toFixed(0)) + feeSat;
             if (typeof vNum == "number" && vNum > 0) {
               if (availableBalanceNum < vNum) {