diff --git a/app/models/article_version.rb b/app/models/article_version.rb
index c447bd55..9bed9aa3 100644
--- a/app/models/article_version.rb
+++ b/app/models/article_version.rb
@@ -40,14 +40,13 @@ class ArticleVersion < ApplicationRecord
   validates :price, numericality: { greater_than_or_equal_to: 0 }
   validates :group_order_granularity, numericality: { greater_than_or_equal_to: 0 }
   validates :deposit, :tax, numericality: true
-  validates :minimum_order_quantity,
-            numericality: { allow_nil: true, only_integer: false, if: :supplier_order_unit_is_si_convertible }
-  validates :minimum_order_quantity,
-            numericality: { allow_nil: true, only_integer: true, unless: :supplier_order_unit_is_si_convertible }
+  validates :minimum_order_quantity, numericality: { allow_nil: true }
+
   # validates_uniqueness_of :name, :scope => [:supplier_id, :deleted_at, :type], if: Proc.new {|a| a.supplier.shared_sync_method.blank? or a.supplier.shared_sync_method == 'import' }
   # validates_uniqueness_of :name, :scope => [:supplier_id, :deleted_at, :type, :unit, :unit_quantity]
   validate :uniqueness_of_name
   validate :only_one_unit_type
+  validate :minimum_order_quantity_as_integer, unless: :supplier_order_unit_is_si_convertible
 
   # Replace numeric seperator with database format
   localize_input_of :price, :tax, :deposit
@@ -117,13 +116,7 @@ def minimum_order_quantity=(value)
     if value.blank?
       self[:minimum_order_quantity] = nil
     else
-      value = value.gsub(I18n.t('number.format.separator'), '.') if value.is_a?(String)
-      begin
-        value = value.to_i if Float(value) % 1 == 0
-      rescue ArgumentError
-        # not any number -> let validation handle this
-      end
-      super(value)
+      super
     end
   end
 
@@ -190,6 +183,17 @@ def uniqueness_of_name
     end
   end
 
+  def minimum_order_quantity_as_integer
+    begin
+      return if Float(minimum_order_quantity) % 1 == 0
+    rescue ArgumentError, TypeError
+      # not any number -> let numericality validation handle this
+      return
+    end
+
+    errors.add(:minimum_order_quantity, :only_integer)
+  end
+
   def only_one_unit_type
     return if unit.blank? || supplier_order_unit.blank?
 
diff --git a/app/models/order_article.rb b/app/models/order_article.rb
index 0b29c4d4..a176675f 100644
--- a/app/models/order_article.rb
+++ b/app/models/order_article.rb
@@ -81,6 +81,7 @@ def update_results!
   #      4        |    5     |     4     |           2
   #
   def calculate_units_to_order(quantity, tolerance = 0)
+    return 0 if !price.minimum_order_quantity.nil? && quantity + tolerance < price.minimum_order_quantity
     return price.minimum_order_quantity if quantity > 0 && !price.minimum_order_quantity.nil? && quantity < price.minimum_order_quantity && quantity + tolerance >= price.minimum_order_quantity
 
     unit_size = price.convert_quantity(1, price.supplier_order_unit, price.group_order_unit)
diff --git a/config/locales/de.yml b/config/locales/de.yml
index bf0cdd7c..6a699ea6 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -272,6 +272,8 @@ de:
             name:
               taken: Name ist bereits vergeben
               taken_with_unit: Name und Einheit sind bereits vergeben
+            minimum_order_quantity:
+              only_integer: Muss eine Ganzzahl sein, wenn die Liefereinheit eine Stückeinheit ist.
         supplier:
           attributes:
             shared_sync_method:
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 480243cb..6129e6dc 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -274,6 +274,8 @@ en:
             name:
               taken: name is already taken
               taken_with_unit: name and unit are already taken
+            minimum_order_quantity:
+              only_integer: Must be an integer if supplier order unit is a piece unit
         supplier:
           attributes:
             shared_sync_method:
diff --git a/spec/factories/article.rb b/spec/factories/article.rb
index f64cfab1..ce6e6b39 100644
--- a/spec/factories/article.rb
+++ b/spec/factories/article.rb
@@ -10,6 +10,7 @@
         order_number { nil }
         unit_quantity { nil }
         unit { nil }
+        minimum_order_quantity { nil }
         supplier_order_unit { 'XPK' }
         group_order_unit { 'XPK' }
         billing_unit { 'XPK' }
@@ -23,6 +24,7 @@
                     order_number: evaluator.order_number,
                     unit_quantity: evaluator.unit_quantity,
                     unit: evaluator.unit,
+                    minimum_order_quantity: evaluator.minimum_order_quantity,
                     supplier_order_unit: evaluator.supplier_order_unit,
                     group_order_unit: evaluator.group_order_unit,
                     billing_unit: evaluator.billing_unit,
diff --git a/spec/models/order_article_spec.rb b/spec/models/order_article_spec.rb
index a0bc9671..78f46d4e 100644
--- a/spec/models/order_article_spec.rb
+++ b/spec/models/order_article_spec.rb
@@ -213,4 +213,59 @@ def goa_reload
       # end
     end
   end
+
+  describe 'minimum order quantity' do
+    let(:order) { create(:order, article_ids: [article.id], starts: 1.week.ago) }
+    let(:oa) { order.order_articles.first }
+    let(:go) { create(:group_order, order: order) }
+    let(:goa) { create(:group_order_article, group_order: go, order_article: oa) }
+
+    shared_context 'minimum order quantity' do |quantity|
+      before do
+        goa.update_quantities(quantity[:quantity], quantity[:tolerance])
+        oa.update_results!
+        oa.reload
+      end
+
+      it 'is calculated correctly' do
+        expect(oa.units_to_order).to eq quantity[:expected_units_to_order]
+      end
+    end
+
+    context 'without unit_quantity' do
+      let(:article) { create(:article, minimum_order_quantity: 10) }
+
+      context 'doesn\'t order anything, if the minimum order quantity hasn\'t been reached' do
+        include_examples 'minimum order quantity', { quantity: 4, tolerance: 0, expected_units_to_order: 0 }
+      end
+
+      context 'orders the minimum order quantity, if tolerance allows for it' do
+        include_examples 'minimum order quantity', { quantity: 9, tolerance: 1, expected_units_to_order: 10 }
+      end
+
+      context 'orders the desired amount, if minimum order quantity has been surpassed' do
+        include_examples 'minimum order quantity', { quantity: 12, tolerance: 1, expected_units_to_order: 12 }
+      end
+    end
+
+    context 'with unit_quantity' do
+      let(:article) { create(:article, minimum_order_quantity: 2, unit_quantity: 5) }
+
+      context 'doesn\'t order anything if the minimum order quantity hasn\'t been reached' do
+        include_examples 'minimum order quantity', { quantity: 4, tolerance: 0, expected_units_to_order: 0 }
+      end
+
+      context 'orders the minimum order quantity if tolerance allows for it' do
+        include_examples 'minimum order quantity', { quantity: 9, tolerance: 1, expected_units_to_order: 2 }
+      end
+
+      context 'orders a lower amount, even if minimum order quantity has been surpassed, but unit_quantity demands it' do
+        include_examples 'minimum order quantity', { quantity: 12, tolerance: 1, expected_units_to_order: 2 }
+      end
+
+      context 'orders the exact amount, if minimum order quantity has been surpassed and unit_quantity allows for it' do
+        include_examples 'minimum order quantity', { quantity: 14, tolerance: 1, expected_units_to_order: 3 }
+      end
+    end
+  end
 end