diff --git a/classes/tax/TaxRulesTaxManager.php b/classes/tax/TaxRulesTaxManager.php
index 99cbea94d..ba6b07456 100644
--- a/classes/tax/TaxRulesTaxManager.php
+++ b/classes/tax/TaxRulesTaxManager.php
@@ -111,10 +111,10 @@ class TaxRulesTaxManagerCore implements TaxManagerInterface
 					 break;
 			}
 
-			self::$cache_tax_calculator[$postcode.'-'.$this->type] = new TaxCalculator($taxes, $behavior);
+			self::$cache_tax_calculator[(int)$this->address->id_country.'-'.$postcode.'-'.$this->type] = new TaxCalculator($taxes, $behavior);
 		}
 
-		return self::$cache_tax_calculator[$postcode.'-'.$this->type];
+		return self::$cache_tax_calculator[(int)$this->address->id_country.'-'.$postcode.'-'.$this->type];
 	}
 }