diff --git a/src/Sylius/Component/Shipping/Calculator/FlatRateCalculator.php b/src/Sylius/Component/Shipping/Calculator/FlatRateCalculator.php
index 994699373ae..de20bdc1169 100644
--- a/src/Sylius/Component/Shipping/Calculator/FlatRateCalculator.php
+++ b/src/Sylius/Component/Shipping/Calculator/FlatRateCalculator.php
@@ -28,7 +28,7 @@ class FlatRateCalculator extends Calculator
      */
     public function calculate(ShippingSubjectInterface $subject, array $configuration)
     {
-        return $configuration['amount'];
+        return (int)$configuration['amount'];
     }
 
     /**
diff --git a/src/Sylius/Component/Shipping/Calculator/FlexibleRateCalculator.php b/src/Sylius/Component/Shipping/Calculator/FlexibleRateCalculator.php
index ab3ce1dbe25..5029ef1c1d3 100644
--- a/src/Sylius/Component/Shipping/Calculator/FlexibleRateCalculator.php
+++ b/src/Sylius/Component/Shipping/Calculator/FlexibleRateCalculator.php
@@ -41,7 +41,7 @@ public function calculate(ShippingSubjectInterface $subject, array $configuratio
             $additionalItems = $additionalItemLimit >= $additionalItems ? $additionalItems : $additionalItemLimit;
         }
 
-        return $firstItemCost + ($additionalItems * $additionalItemCost);
+        return (int)($firstItemCost + ($additionalItems * $additionalItemCost));
     }
 
     /**
diff --git a/src/Sylius/Component/Shipping/Calculator/PerItemRateCalculator.php b/src/Sylius/Component/Shipping/Calculator/PerItemRateCalculator.php
index eeab8f9339d..585db6f7e42 100644
--- a/src/Sylius/Component/Shipping/Calculator/PerItemRateCalculator.php
+++ b/src/Sylius/Component/Shipping/Calculator/PerItemRateCalculator.php
@@ -26,7 +26,7 @@ class PerItemRateCalculator extends Calculator
      */
     public function calculate(ShippingSubjectInterface $subject, array $configuration)
     {
-        return $configuration['amount'] * $subject->getShippingItemCount();
+        return (int)($configuration['amount'] * $subject->getShippingItemCount());
     }
 
     /**