number_to_currency(number, options = {}) public

Formats a number into a currency string (e.g., $13.65). You can customize the format in the options hash.

The currency unit and number formatting of the current locale will be used unless otherwise specified in the provided options. No currency conversion is performed. If the user is given a way to change their locale, they will also be able to change the relative value of the currency displayed with this helper. If your application will ever support multiple locales, you may want to specify a constant :locale option or consider using a library capable of currency conversion.

Options

  • :locale - Sets the locale to be used for formatting (defaults to current locale).

  • :precision - Sets the level of precision (defaults to 2).

  • :unit - Sets the denomination of the currency (defaults to “$”).

  • :separator - Sets the separator between the units (defaults to “.”).

  • :delimiter - Sets the thousands delimiter (defaults to “,”).

  • :format - Sets the format for non-negative numbers (defaults to “%u%n”). Fields are %u for the currency, and %n for the number.

  • :negative_format - Sets the format for negative numbers (defaults to prepending a hyphen to the formatted number given by :format). Accepts the same fields than :format, except %n is here the absolute value of the number.

  • :raise - If true, raises InvalidNumberError when the argument is invalid.

  • :strip_insignificant_zeros - If true removes insignificant zeros after the decimal separator (defaults to false).

Examples

number_to_currency(1234567890.50)                    # => $1,234,567,890.50
number_to_currency(1234567890.506)                   # => $1,234,567,890.51
number_to_currency(1234567890.506, precision: 3)     # => $1,234,567,890.506
number_to_currency(1234567890.506, locale: :fr)      # => 1 234 567 890,51 €
number_to_currency("123a456")                        # => $123a456

number_to_currency("123a456", raise: true)           # => InvalidNumberError

number_to_currency(-0.456789, precision: 0)
# => "$0"
number_to_currency(-1234567890.50, negative_format: "(%u%n)")
# => ($1,234,567,890.50)
number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "")
# => R$1234567890,50
number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "", format: "%n %u")
# => 1234567890,50 R$
number_to_currency(1234567890.50, strip_insignificant_zeros: true)
# => "$1,234,567,890.5"
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August 29, 2008
6 thanks

Brazilian Real (R$ 1.200,95)

helper:

def number_to_currency_br(number)
  number_to_currency(number, :unit => "R$ ", :separator => ",", :delimiter => ".")
end
October 20, 2008
3 thanks

number_to_euro

in small cells:

12  
€
-->
12 €

def number_to_euro(amount)
  number_to_currency(amount,:unit=>'€').gsub(' ',nbsp)
end
January 15, 2010
3 thanks

Use this in controllers

Sometimes you’re gonna need this in controllers. Just put this in the controller:

include ActionView::Helpers::NumberHelper
October 4, 2011
2 thanks

How to change format automatically depending on locale...

… without passing locale option.

In your application_helper.rb (or in other helper) place following code:

def number_to_currency(number, options = {})
  options[:locale] ||= I18n.locale
  super(number, options)
end

Then, in your locale files:

en-GB:
  number:
    currency:
      format:
        format: "%n %u"
        unit: "USD"

And that is it :)

November 19, 2014
1 thank

Bangladeshi Taka (BDT 1,200.95)

Code example 

def to_bdt(amount)
  number_to_currency(amount, :unit => "BDT ", :separator => ".", :delimiter => ",")
end
October 24, 2012
0 thanks

If you happen to face some weird rounding issue...

i.e.

helper.number_to_currency(187)
=> "190 kr"

check out your… translations! Especially ‘significant’ key… In my case it was

number:
   currency:
     format:
       significant: 'false'

that broke rounding. It should have been

number:
   currency:
     format:
       significant: ! 'false'

And now it works perfectly

helper.number_to_currency(187)
=> "187 kr"