diff --git a/app/models/proposal.rb b/app/models/proposal.rb
index b14d2e194..f7c1c5078 100644
--- a/app/models/proposal.rb
+++ b/app/models/proposal.rb
@@ -65,7 +65,7 @@ class Proposal < ActiveRecord::Base
   end
 
   def code
-    "#{Setting.value_for("proposal_code_prefix")}-#{created_at.strftime('%Y-%M')}-#{id}"
+    "#{Setting.value_for("proposal_code_prefix")}-#{created_at.strftime('%Y-%m')}-#{id}"
   end
 
   def after_commented
diff --git a/spec/models/proposal_spec.rb b/spec/models/proposal_spec.rb
index ac7c1edfb..6e5acb379 100644
--- a/spec/models/proposal_spec.rb
+++ b/spec/models/proposal_spec.rb
@@ -125,7 +125,7 @@ describe Proposal do
   it "should have a code" do
     Setting.find_by(key: "proposal_code_prefix").update(value: "TEST")
     proposal = create(:proposal)
-    expect(proposal.code).to eq "TEST-#{proposal.created_at.strftime('%Y-%M')}-#{proposal.id}"
+    expect(proposal.code).to eq "TEST-#{proposal.created_at.strftime('%Y-%m')}-#{proposal.id}"
   end
 
   describe "#editable?" do