diff --git a/public/views/modals/inputAmount.html b/public/views/modals/inputAmount.html
index e9192df9c..81e189df1 100644
--- a/public/views/modals/inputAmount.html
+++ b/public/views/modals/inputAmount.html
@@ -15,10 +15,9 @@
   <ion-content>
     <div ng-show="!specificAmount">
       <div class="send-amount row" ng-style="{'background-color':index.backgroundColor}">
-        <div class="size-48" ng-show="!showAlternativeAmount">{{amount}}</div>
-        <div class="size-21 text-light" ng-show="!showAlternativeAmount">{{globalResult}} {{amountResult}} {{alternativeIsoCode}}</div>
-        <div class="size-48" ng-show="showAlternativeAmount">${{alternativeAmount}}</div>
-        <div class="size-21 text-light" ng-show="showAlternativeAmount">{{globalResult}} {{alternativeResult}} {{unitName}}</div>
+        <div class="size-48">{{amount || '-'}}</div>
+        <div class="size-21 text-light" ng-show="!showAlternativeAmount">{{globalResult}} [{{amountResult || 0}} {{alternativeIsoCode}}]</div>
+        <div class="size-21 text-light" ng-show="showAlternativeAmount">{{globalResult}} [{{alternativeResult || 0}} {{unitName}}]</div>
       </div>
 
       <div class="button-content text-center size-10 df">
diff --git a/src/js/controllers/modals/inputAmount.js b/src/js/controllers/modals/inputAmount.js
index e0833a10b..0335655dd 100644
--- a/src/js/controllers/modals/inputAmount.js
+++ b/src/js/controllers/modals/inputAmount.js
@@ -10,7 +10,7 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
     var config = configService.getSync().wallet.settings;
     $scope.unitName = config.unitName;
     $scope.alternativeIsoCode = config.alternativeIsoCode;
-    $scope.specificAmount = $scope.specificAlternativeAmount = null;
+    $scope.specificAmount = $scope.specificAlternativeAmount = '';
     $scope.isCordova = platformInfo.isCordova;
     unitToSatoshi = config.unitToSatoshi;
     satToUnit = 1 / unitToSatoshi;
@@ -26,40 +26,18 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
 
   $scope.toggleAlternative = function() {
     $scope.showAlternativeAmount = !$scope.showAlternativeAmount;
-    var amount;
-
-    if ($scope.showAlternativeAmount) {
-      $scope.alternativeAmount = $scope.amountResult;
-      amount = format($scope.amount);
-      $scope.alternativeResult = isOperator(lodash.last(amount)) ? evaluate(amount.slice(0, -1)) : evaluate(amount);
-    } else {
-      $scope.amount = $scope.alternativeResult;
-      amount = format($scope.alternativeAmount);
-      $scope.amountResult = isOperator(lodash.last(amount)) ? evaluate(amount.slice(0, -1)) : evaluate(amount);
-    }
-    $scope.globalResult = null;
   };
 
   $scope.pushDigit = function(digit) {
-    var amount = $scope.showAlternativeAmount ? $scope.alternativeAmount.toString() : $scope.amount.toString();
+    if ($scope.amount && $scope.amount.length >= 20) return;
 
-    if (amount.length >= 20) return;
-    if (amount == '0') {
-      if (digit == 0) return;
-      processAmount(digit);
-      return;
-    }
-    processAmount(amount + digit);
+    $scope.amount = $scope.amount + digit;
+    processAmount($scope.amount);
   };
 
   $scope.pushOperator = function(operator) {
-    if ($scope.showAlternativeAmount) {
-      if (!$scope.alternativeAmount || $scope.alternativeAmount.length == 0) return;
-      $scope.alternativeAmount = _pushOperator($scope.alternativeAmount);
-    } else {
-      if (!$scope.amount || $scope.amount.length == 0) return;
-      $scope.amount = _pushOperator($scope.amount);
-    }
+    if (!$scope.amount || $scope.amount.length == 0) return;
+    $scope.amount = _pushOperator($scope.amount);
 
     function _pushOperator(val) {
       if (!isOperator(lodash.last(val))) {
@@ -77,27 +55,26 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
     return false;
   };
 
-  $scope.removeDigit = function() {
-    var amount = $scope.showAlternativeAmount ? $scope.alternativeAmount : $scope.amount;
+  function isExpression(val) {
+    var regex = /^\d+(\.?\d?)+$/;
+    var match = regex.exec(val);
 
-    if (amount && amount.toString().length == 0) {
+    if (match) return false;
+    return true;
+  };
+
+  $scope.removeDigit = function() {
+    if ($scope.amount.toString().length == 1) {
       resetAmount();
       return;
     }
 
-    amount = amount.toString().slice(0, -1);
-
-    if ($scope.showAlternativeAmount)
-      $scope.alternativeAmount = amount;
-    else
-      $scope.amount = amount;
-
-    processAmount(amount);
+    $scope.amount = $scope.amount.slice(0, -1);
+    processAmount($scope.amount);
   };
 
   function resetAmount() {
-    $scope.amount = $scope.alternativeAmount = $scope.alternativeResult = $scope.amountResult = 0;
-    $scope.globalResult = null;
+    $scope.amount = $scope.alternativeResult = $scope.amountResult = $scope.globalResult = '';
   };
 
   function processAmount(val) {
@@ -106,24 +83,13 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
       return;
     }
 
-    if ($scope.showAlternativeAmount) {
-      if ($scope.alternativeAmount == 0 && val == '.') {
-        $scope.alternativeAmount += val;
-      }
-    } else {
-      if ($scope.amount == 0 && val == '.') {
-        $scope.amount += val;
-      }
-    }
-
     var formatedValue = format(val);
     var result = evaluate(formatedValue);
 
     if (lodash.isNumber(result)) {
-      $scope.amount = $scope.alternativeAmount = val;
-      $scope.globalResult = result + ' =';
-      $scope.amountResult = toFiat(result);
-      $scope.alternativeResult = fromFiat(result);
+      $scope.globalResult = isExpression(val) ? '= ' + result.toFixed(2) : '';
+      $scope.amountResult = toFiat(result).toFixed(2);
+      $scope.alternativeResult = fromFiat(result).toFixed(2);
     }
   };
 
@@ -140,9 +106,9 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
     try {
       result = $scope.$eval(val);
     } catch (e) {
-      return null;
+      return 0;
     }
-    if (result == 'Infinity' || lodash.isNaN(result)) return null;
+    if (result == 'Infinity' || lodash.isNaN(result)) return 0;
     return result;
   };
 
@@ -161,7 +127,7 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
 
     if ($scope.showAlternativeAmount) {
       amount = $scope.alternativeResult;
-      alternativeAmount = evaluate(format($scope.alternativeAmount));
+      alternativeAmount = evaluate(format($scope.amount));
     } else {
       amount = evaluate(format($scope.amount));
       alternativeAmount = toFiat(amount);
@@ -174,10 +140,10 @@ angular.module('copayApp.controllers').controller('inputAmountController', funct
         $scope.specificAmountBtc = (amountSat * satToBtc).toFixed(8);
       }
 
-      $scope.specificAmount = amount.toFixed(2);
-      $scope.specificAlternativeAmount = alternativeAmount.toFixed(2);
+      $scope.specificAmount = amount;
+      $scope.specificAlternativeAmount = alternativeAmount;
     } else {
-      self.setAmount(amount.toFixed(2), alternativeAmount.toFixed(2), $scope.showAlternativeAmount);
+      self.setAmount(amount, alternativeAmount, $scope.showAlternativeAmount);
       $scope.cancel();
     }
   };