Global Lua Modules/Formatnum

Formatnum
Information
Type	Lua module
Release status	Stable
Test suite status	Failed
Description	Formats numbers
Author(s)	Dessamator
Other attribution	commons:Module:Formatnum
Updated	November 17, 2025
Code	Module:Formatnum
Dependencies	Module:Arguments

It is used in:

• Template:Formatnum

This module formats numbers based on the formatting rules of each language.

Installation

Lua installation
Module:	Create Module:Formatnum on your wiki with the following code:
Template:	Create Template:Formatnum on your wiki with the following code:
Template usage:	The template can be used with the following syntax:

Usage

{{formatnum|1=value|2=lang|prec=prec|sep=compact}}

Parameters

• lang — language code as a string (e.g. en, de, etc.). If the language is not specified (nil or empty string) or not supported, the current user's language will be used.

The lang named parameter is also a supported alias of the 2nd parameter.

The value "arabic-indic" is also currently supported as an alias, and replaced by a supported language code.

• See formatNum() below for the expected values and the description of other parameter values.

Note:

This template internally uses {{#invoke:Formatnum|main}} to pass indirectly its parameters to the main() function of this module in the parent frame.

formatNum()

This function converts an value into a localized number.

Usage:

formatted_string = formatnum.formatNum(value, lang, prec, compact)

Parameters:

• value — as an ASCII-only number or string. If the string cannot be converted to a number with Lua's tonumber(), that string will be returned as is.
• lang — language code as a string (e.g. en, de, etc.). If that language is not supported, localized digits and separators will not be used (except for a few languages).
• prec — if not nil and not negative, this is the number of digits in displayed decimals (by truncating the decimals in excess or by adding zeroes). Valid range: 0 to 14.
  • when prec is not specified or nil, the decimal separator is shown only if there are 1 or more visible decimals;
  • when prec is negative or non integer it is treated like nil;
  • when prec is 0, there will never be any decimal separator or any displayed decimals;
  • when prec is positive, a decimal separator will always be present before this number of decimals, but when prec is higher than 14, it is treated like 14.
• compact — if this option is not nil and not false, don't return any localized grouping separators (the localized decimal separator and digits are still used).

Examples:

• formatted_string = formatnum.formatNum(12345.123) — convert to user's language, using localized digits and separators
• formatted_string = formatnum.formatNum(12345.123,'') — same thing (language code not supported)
• formatted_string = formatnum.formatNum(12345.123,'default') — same thing (language code not supported)
• formatted_string = formatnum.formatNum(12345.123,'en') — convert to English: "12,345.123"
• formatted_string = formatnum.formatNum(12345.123,'fr') — convert to French: "12 345,123"
• formatted_string = formatnum.formatNum(12345.123,'fr',2) — same thing but limit to 2 decimals: "12 345,12"
• formatted_string = formatnum.formatNum(12345,'fr',2) — same thing (2 null decimals are padded): "12 345,00"
• formatted_string = formatnum.formatNum(12345,'fr',2,true) — same thing but without grouping separators: "12345,00"

Limitations:

• Same limit of 20 "KnownLanguages" (because it still depends on mw.Language module in order to detect localized digits and separators).
• When specifying the "prec" parameter, decimals in excess are just truncated, and the least significant digit is not rounded.

Text above can be found here (edit)