CPF/CNPJ

This gem does some CPF/CNPJ magic. It allows you to create, validate and format CPF/CNPJ, even through the command-line.

Just making my life easier when filling these damn numbers on internet bankings and government sites.

For ActiveModel/ActiveRecord validations, please check https://github.com/fnando/validators.

Installation

Add this line to your application's Gemfile:

gem "cpf_cnpj"

And then execute:

$ bundle

Or install it yourself as:

$ gem install cpf_cnpj

Usage

Ruby API

This library has the same API for both CNPJ/CPF, so only one of them is documented below.

Note

This library already supports the new alphanumeric CNPJ algorithm that will be available starting July 2026. For more information, see https://www.gov.br/receitafederal/pt-br/acesso-a-informacao/acoes-e-programas/programas-e-atividades/cnpj-alfanumerico.

require "cpf_cnpj"

CPF.format(number)            # Format CPF (xxx.xxx.xxx-xx)
CPF.valid?(number)            # Check if a CPF is valid
CPF.generate                  # Generate a random CPF number
CPF.generate(true)            # Generate a formatted number

cpf = CPF.new(number)
cpf.formatted                 # Return formatted CPF (xxx.xxx.xxx-xx)
cpf.stripped                  # Return stripped CPF (xxxxxxxxxxx)
cpf.valid?                    # Check if CPF is valid
cpf.number_without_verifier   # Return CPF without verifier digits

Strict Validation

By default, validations will strip any characters that aren't numbers. This means that 532#####820------857\n96 is considered a valid number. To perform a strict validation use strict: true.

CPF.valid?(number, strict: true)

Command-line

This library gives you two binaries: cpf and cnpj.

$ cpf --check 532.820.857-96
$ $?
0

$ cpf --check 53282085796
$ $?
0

$ cpf --format 53282085796
532.820.857-96

$ cpf --strip 532.820.857-96
53282085796

$ cpf --generate
417.524.931-17

$ cpf --generate --strip
76001454809

$ echo 76001454809 | cpf -f
760.014.548-09

Contributing

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