diff --git a/back-office/app/controllers/items_controller.rb b/back-office/app/controllers/items_controller.rb
index 66405aa..a3a9b02 100644
--- a/back-office/app/controllers/items_controller.rb
+++ b/back-office/app/controllers/items_controller.rb
@@ -3,4 +3,16 @@ class ItemsController < ApplicationController
     conf.columns[:unit].form_ui = :select
     conf.columns[:sub_category].form_ui = :select
   end
+
+  def check_availability
+    @suppliers = Supplier.order(:name).all
+    @selected_supplier = Supplier.find_by_id(params[:supplier_id])
+    @items = @selected_supplier.try(:items) || []
+    @codes_to_check = params[:codes] || ""
+    @codes_to_check_array = @codes_to_check.split("\n").reject { |code| code.strip.blank? }.map(&:strip)
+    items_to_check = @items.map { |i| i.code.strip }
+
+    @missing_from_database =  (@codes_to_check_array - items_to_check) || []
+    @missing_from_codes = (items_to_check - @codes_to_check_array) || []
+  end
 end
diff --git a/back-office/app/views/items/check_availability.html.erb b/back-office/app/views/items/check_availability.html.erb
new file mode 100644
index 0000000..98ec3b5
--- /dev/null
+++ b/back-office/app/views/items/check_availability.html.erb
@@ -0,0 +1,34 @@
+<%= form_tag('/items/check_availability') do %>
+  <p><label for="supplier_id">Supplier: </label>
+  <%= select_tag "supplier_id", options_from_collection_for_select(@suppliers, "id", "name", @selected_supplier.try(:id)) %></p>
+
+  <p><label for="codes"> 
+    Codes to check:
+  </label><br />
+  <%= text_area_tag "codes", @codes_to_check, rows: 20, columns: 50 %></p>
+
+  <p><%= submit_tag "Check" %></p>
+<% end %>
+
+<div>
+<h2> In database: <%= @items.length %>, in file: <%= @codes_to_check_array.length %> </h2>
+</div>
+
+<div>
+<h2>Not in database (<%= @missing_from_database.length %>): </h2>
+<br />
+<% @missing_from_database.each do |code| %>
+  <%= code %><br /> 
+<% end %>
+
+</div>
+
+<div>
+<h2>Not in file (<%= @missing_from_codes.length %>): </h2>
+<br />
+<% @missing_from_codes.each do |code| %>
+  <%= code %><br />
+<% end %>
+
+</div>
+
diff --git a/back-office/config/initializers/rails_admin.rb b/back-office/config/initializers/rails_admin.rb
index c7034d3..f3841f0 100644
--- a/back-office/config/initializers/rails_admin.rb
+++ b/back-office/config/initializers/rails_admin.rb
@@ -34,6 +34,7 @@ RailsAdmin.config do |config|
 
   config.navigation_static_links = {
   'Orders to Confirm' => '../reports/orders_to_confirm',
-  'Items to Order' => '../reports/items_to_order'
+  'Items to Order' => '../reports/items_to_order',
+  'Check availability' => '../items/check_availability'
   }
 end
diff --git a/back-office/config/routes.rb b/back-office/config/routes.rb
index 3375f60..9c38196 100644
--- a/back-office/config/routes.rb
+++ b/back-office/config/routes.rb
@@ -15,7 +15,13 @@ Rails.application.routes.draw do
   resources :multi_media_descriptions do as_routes end
   resources :sections do as_routes end
   resources :media_types do as_routes end
-  resources :items do as_routes end
+  resources :items do 
+    collection do 
+      get 'check_availability'
+      post 'check_availability'
+    end
+    as_routes 
+  end
   resources :units do as_routes end
   resources :sub_categories do as_routes end
   resources :categories do as_routes end