diff --git a/app/assets/javascripts/admin/products/units_controller.js.coffee b/app/assets/javascripts/admin/products/units_controller.js.coffee
index db005e490a..c9c5807af3 100644
--- a/app/assets/javascripts/admin/products/units_controller.js.coffee
+++ b/app/assets/javascripts/admin/products/units_controller.js.coffee
@@ -5,6 +5,13 @@ angular.module("admin.products")
     $scope.placeholder_text = ""
 
     $scope.$watchCollection '[product.variant_unit_with_scale, product.master.unit_value_with_description]', ->
+      $scope.processVariantUnitWithScale()
+      $scope.processUnitValueWithDescription()
+      $scope.placeholder_text = new OptionValueNamer($scope.product.master).name()
+
+    $scope.variant_unit_options = VariantUnitManager.variantUnitOptions()
+
+    $scope.processVariantUnitWithScale = ->
       if $scope.product.variant_unit_with_scale
         match = $scope.product.variant_unit_with_scale.match(/^([^_]+)_([\d\.]+)$/)
         if match
@@ -16,6 +23,7 @@ angular.module("admin.products")
       else
         $scope.product.variant_unit = $scope.product.variant_unit_scale = null
 
+    $scope.processUnitValueWithDescription = ->
       if $scope.product.master.hasOwnProperty("unit_value_with_description")
         match = $scope.product.master.unit_value_with_description.match(/^([\d\.]+(?= |$)|)( |)(.*)$/)
         if match
@@ -24,10 +32,6 @@ angular.module("admin.products")
           $scope.product.master.unit_value *= $scope.product.variant_unit_scale if $scope.product.master.unit_value && $scope.product.variant_unit_scale
           $scope.product.master.unit_description = match[3]
 
-      $scope.placeholder_text = new OptionValueNamer($scope.product.master).name()
-
-    $scope.variant_unit_options = VariantUnitManager.variantUnitOptions()
-
     $scope.hasVariants = (product) ->
       Object.keys(product.variants).length > 0
 
diff --git a/spec/javascripts/unit/admin/products/units_controller_spec.js.coffee b/spec/javascripts/unit/admin/products/units_controller_spec.js.coffee
new file mode 100644
index 0000000000..c5f104f07a
--- /dev/null
+++ b/spec/javascripts/unit/admin/products/units_controller_spec.js.coffee
@@ -0,0 +1,55 @@
+describe "unitsCtrl", ->
+  ctrl = null
+  scope = null
+  product = null
+
+  beforeEach ->
+    module('admin.products')
+    inject ($rootScope, $controller, VariantUnitManager) ->
+      scope = $rootScope
+      ctrl = $controller 'unitsCtrl', {$scope: scope, VariantUnitManager: VariantUnitManager}
+
+  describe "interpretting variant_unit_with_scale", ->
+    it "splits string with one underscore and stores the two parts", ->
+      scope.product.variant_unit_with_scale = "weight_1000"
+      scope.processVariantUnitWithScale()
+      expect(scope.product.variant_unit).toEqual "weight"
+      expect(scope.product.variant_unit_scale).toEqual 1000
+
+    it "interprets strings with no underscore as variant_unit", ->
+      scope.product.variant_unit_with_scale = "items"
+      scope.processVariantUnitWithScale()
+      expect(scope.product.variant_unit).toEqual "items"
+      expect(scope.product.variant_unit_scale).toEqual null
+
+    it "sets variant_unit and variant_unit_scale to null", ->
+      scope.product.variant_unit_with_scale = null
+      scope.processVariantUnitWithScale()
+      expect(scope.product.variant_unit).toEqual null
+      expect(scope.product.variant_unit_scale).toEqual null
+
+  describe "interpretting unit_value_with_description", ->
+    beforeEach ->
+      scope.product.master = {}
+
+    describe "when a variant_unit_scale is present", ->
+      beforeEach ->
+        scope.product.variant_unit_scale = 1
+
+      it "splits by whitespace in to unit_value and unit_description", ->
+        scope.product.master.unit_value_with_description = "12 boxes"
+        scope.processUnitValueWithDescription()
+        expect(scope.product.master.unit_value).toEqual 12
+        expect(scope.product.master.unit_description).toEqual "boxes"
+
+      it "uses whole string as unit_value when only numerical characters are present", ->
+        scope.product.master.unit_value_with_description = "12345"
+        scope.processUnitValueWithDescription()
+        expect(scope.product.master.unit_value).toEqual 12345
+        expect(scope.product.master.unit_description).toEqual ''
+
+      it "uses whole string as description when string does not start with a number", ->
+        scope.product.master.unit_value_with_description = "boxes 12"
+        scope.processUnitValueWithDescription()
+        expect(scope.product.master.unit_value).toEqual null
+        expect(scope.product.master.unit_description).toEqual "boxes 12"