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Locale Lab

Unicode CLDR · World Bank Open Data · ECMAScript Intl

Decide which languages to ship next.

Market reach models across 250 territories, working tools for pricing and checking translation, and a field guide to how software breaks in other languages.

See what your languages reachOpen the CLDR explorer

Or read the field guide: 21 short chapters on the technical side of localization.

Dates, numbers, and currencies across 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 with Intl using Unicode CLDR data. A naive parseFloat() reads the German number as 1.234. The CLDR explorer covers additional locales and custom values.

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 chapters6 themes, demos included

01 · The Atlas

Coverage, candidates, and the budget ask

Name the languages a product already ships; the Atlas reports what that list reaches across 250 territories, and what each language it misses would add.

Every figure traces to Unicode CLDR or World Bank Open Data. Read the methodology

Reach today

Coverage workbench

Your share of the 5.8B people online, and the markets you do not reach.

What to add next

Launch planner

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

The shortlist

Compare markets

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

For the budget meeting

Executive briefing

A one-page recommendation with the numbers, the risks, and a sequence.

02 · The Tools

The utilities a localization round runs on

All four compute in the browser. The explorer and the estimator keep their state in the URL, so a configured view or estimate is a link.

All tools overview
Locale Reference

CLDR explorer

One date, number, or price formatted across every locale in a set. Flags what breaks parsers: swapped separators, invisible spaces, non-Latin digits, bidi marks. Exports Markdown and CSV.

Open the explorer
Delivery gate

String audit

Monolingual linter and bilingual delivery gate. Checks concatenation, broken ICU, dropped placeholders, and the plural arms the target locale requires, from Intl.PluralRules.

Run the audit
Layout fit

Text expansion

One UI string machine-translated into 55 languages, then measured in a font the reader picks: characters, pixel width, and the ink height that clips Thai and Burmese in a control sized to Latin.

Measure a string
What a round costs

Budget estimator

Prices a translation round per locale. Applies a per-language rate index, translation memory leverage discounts, and engineering setup costs (RTL, webfonts, i18n framework).

Open the estimator

03 · The Field Guide

21 chapters on how software breaks abroad

Each chapter pairs a short read with a live demo, from the failures anyone can see down to encodings, date systems, and the translation pipeline. The six parts below read in order or stand alone.

Open the field guide
  1. 01

    Getting oriented

    What localization work is made of

    Orientation
  2. 02

    Three visible failures

    Layout swell, formatting, plural grammar

    Text expansionFormattersPlurals & gender
  3. 03

    The Intl toolbox

    The APIs that already know the answer

    Lists & rangesSortingTime zonesCalendarsLocale fallback
  4. 04

    Scripts and layout

    Writing systems meet CSS

    Line-breakingCJK fallbackBiDiRTL mirroring
  5. 05

    Strings, names, and input

    Data that comes from people

    Unicode pitfallsEncodingInput parsingAddress & name
  6. 06

    Shipping translations

    The pipeline, the QA step, the audit

    Translation pipelinePseudolocLQA scoringThe audit

Formatting samples are computed with Intl. Languages and population metrics come from Unicode CLDR. Internet adoption, income, and account ownership come from World Bank Open Data. See how each figure is computed.