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Locale Lab

Unicode CLDR · World Bank Open Data · ECMAScript Intl

Decide which languages to ship next.

Speaker and market data for 250 territories, tools for checking and pricing translation, and a field guide to localization engineering.

See what your languages reachOpen the CLDR explorer

Or read the field guide (21 chapters).

One date, number, and price in 5 locales
Date, number, and currency formatting across selected locales
LocaleDateNumberCurrency
English (US) en-USMar 9, 20261,234,567.89$1,234,567.89
German de-DE09.03.20261.234.567,891.234.567,89 €
Japanese ja-JP2026/03/091,234,567.89￥1,234,568
Hindi hi-IN9 मार्च 202612,34,567.89₹12,34,567.89
Arabic (Egypt) ar-EG٠٩‏/٠٣‏/٢٠٢٦١٬٢٣٤٬٥٦٧٫٨٩‏١٬٢٣٤٬٥٦٧٫٨٩ ج.م.‏

Formatted by Intl from CLDR data. parseFloat() reads the German number as 1.234. Other values and locales: CLDR explorer.

territories
250 territoriesCLDR & World Bank dataset
people online
5.8B people onlineacross those territories
languages
581 languageswith ≥ 0.1% population share
guide chapters
21 guide chaptersin 6 parts, each with a demo

01 · The Atlas

Language coverage and launch planning

Enter the languages a product ships. The Atlas shows who they reach in 250 territories and ranks what each missing language would add.

Sources: Unicode CLDR and World Bank Open Data. Methodology

Coverage

Coverage workbench

How much of the 5.8B people online a language list reaches, and which markets it misses.

Prioritize

Launch planner

Candidate languages ranked on audience, income, and engineering effort.

Compare

Compare markets

Up to four countries side by side, from speaker counts down to date formats.

Report

Executive briefing

A printable one-page recommendation: launch order, reach, cost, and risks.

02 · The Tools

Four tools for a localization release

The explorer and the estimator keep their settings in the URL, so any view can be shared as a link.

All tools
Locale data

CLDR explorer

Formats one date, number, or price in every locale of a set and flags what breaks parsers: swapped separators, invisible spaces, non-Latin digits, bidi marks.

Open the explorer
String QA

String audit

Lints a source file before handoff and checks the translated file before import: concatenation, broken ICU syntax, dropped placeholders, missing plural forms.

Run the audit
Layout

Text expansion

Machine-translates one UI string into 55 languages and measures each in a chosen font: characters, pixel width, and ink height.

Measure a string
Cost

Budget estimator

Per-locale cost and schedule for a translation round, with language-pair rate indexes, TM leverage, and one-time engineering setup (RTL, webfonts, i18n framework).

Open the estimator

03 · The Field Guide

21 chapters on the technical side of localization

Each chapter is a short read with a live demo. Read the 6 parts in order, or open any chapter on its own.

Open the field guide
  1. 01

    Getting oriented

    Terms and standards

    Orientation
  2. 02

    Three visible failures

    Expansion, formatting, plurals

    Text expansionFormattersPlurals & gender
  3. 03

    The Intl toolbox

    Locale data the runtime ships

    Lists & rangesSortingTime zonesCalendarsLocale fallback
  4. 04

    Scripts and layout

    Wrapping, fonts, direction

    Line breakingCJK fallbackBiDiRTL mirroring
  5. 05

    Strings, names, and input

    Data that comes from people

    Unicode stringsEncodingInput parsingNames & addresses
  6. 06

    Shipping translations

    Files, TM, QA, and the audit

    Translation pipelinePseudolocLQA scoringThe audit

Formatting samples come from Intl; languages and population from Unicode CLDR; internet use, income, and account ownership from World Bank Open Data.