diff --git a/app/models/calculator/weight.rb b/app/models/calculator/weight.rb
index 410a53b2f8..a10245bc55 100644
--- a/app/models/calculator/weight.rb
+++ b/app/models/calculator/weight.rb
@@ -1,7 +1,11 @@
+require 'spree/localized_number'
+
 module Calculator
   class Weight < Spree::Calculator
+    extend Spree::LocalizedNumber
     preference :per_kg, :decimal, default: 0.0
     attr_accessible :preferred_per_kg
+    localize_number :preferred_per_kg
 
     def self.description
       I18n.t('spree.weight')
diff --git a/spec/models/calculator/weight_spec.rb b/spec/models/calculator/weight_spec.rb
index c45da8850a..028e82d829 100644
--- a/spec/models/calculator/weight_spec.rb
+++ b/spec/models/calculator/weight_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe Calculator::Weight do
+  it_behaves_like "a model using the LocalizedNumber module", [:preferred_per_kg]
+
   it "computes shipping cost for an order by total weight" do
     variant1 = build(:variant, weight: 10)
     variant2 = build(:variant, weight: 20)