Monthify provides a Month class in a similar style to Date and Time.


Add this line to your application's Gemfile:

gem 'monthify'

And then execute:

$ bundle

Or install it yourself as:

$ gem install monthify


Here are some example usages of the Month class.

this_month = Month.current
last_month = Month.containing(1.month.ago)

# all of these statements are true...
this_month > last_month
(last_month + 1.month) == this_month == this_month
this_month.previous == last_month

jan_2012 =, 1)
# these are also true...
jan_2012.first_day ==, 1, 1)
jan_2012.last_day ==, 1, 31)
jan_2012.first_moment == jan_2012.first_date.beginning_of_day
jan_2012.last_moment == jan_2012.last_date.end_of_day


Object#to_month == Month.current == Month.current


This is equivalent to calling #to_month

Month( == Month.current

ActiveRecord integration

To treat a field in an ActiveRecord model like a month, do the following:

  1. Create a Date column on the table with the same name as the field you want
  2. Tell the model to serialize that field as a Month

an example...

# in db/migrate/20121023060410_add_month_billed_to_statements.rb

def up
  add_column :statements, :month_billed, :date

# in app/models/statement.rb

serialize :month_billed, Month


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request