About this tool
Language Code Lookup is a focused reference for the language codes used to tag content for browsers, search engines, payment platforms, mobile apps, and i18n libraries. The list covers every ISO 639-1 entry (the two-letter codes used in HTML lang and most user-facing locale UIs) plus the most-needed ISO 639-2/3-only entries that ship as content on the web (Cantonese yue, Central Kurdish ckb, Filipino fil, Min Nan nan, South Azerbaijani azb, Wu wuu, Hakka hak, Tok Pisin tpi, and others). For each language the tool surfaces the alpha-2 code, the alpha-3 terminological code, the alpha-3 bibliographic code where it differs from the terminological one (deu vs ger, fra vs fre, zho vs chi, ces vs cze, isl vs ice, fas vs per, hye vs arm, eus vs baq, kat vs geo, mkd vs mac, mri vs mao, nld vs dut, ron vs rum, slk vs slo, sqi vs alb, mya vs bur, bod vs tib, cym vs wel), the English short name, the language's own native name (endonym), the default script the language is most commonly written in, the text direction (LTR or RTL), the high-level language family, and the most-used BCP 47 tags with region and script subtags (en-US, en-GB; pt-BR, pt-PT; zh-Hans-CN, zh-Hant-TW; sr-Cyrl-RS, sr-Latn-RS; es-419 for Latin America; ar-EG, ar-SA, ar-MA). Three copy-ready snippets are emitted for the selected language: an HTML lang attribute with the matching dir, a block of hreflang link tags for the most common regions, and an Accept-Language header with conservative quality factors. A BCP 47 (RFC 5646) tag validator below parses any pasted tag (en-US, zh-Hant-TW, de-CH-1996, es-419, sr-Cyrl-RS, ar-EG, x-private-tag) into its language subtag, optional extended language, optional script, optional region, optional variants, optional extensions (u, t, and so on), and optional private-use subtag, reports whether each subtag is well-formed against the BCP 47 grammar, applies the recommended case (lowercase language, Title Script, UPPER REGION) to produce a canonical form, and flags the most common authoring mistakes (extended language subtags used outside library catalogs, script subtag present without a region, empty subtags, characters outside the [A-Za-z0-9-] set). Useful for SEO specialists writing hreflang sitemaps, frontend engineers setting the HTML lang attribute for accessibility (the lang attribute is what screen readers use to pick a pronunciation), Next.js, Astro, Nuxt, and Remix developers wiring up i18n routes, backend engineers parsing Accept-Language headers, payment and Stripe Checkout integrators picking a locale field, mobile developers naming Android resource folders (values-zh-rTW, values-pt-rBR) and iOS .lproj directories, and writers and translators looking up a language's endonym before adding a credit line. Everything is local. The data ships statically and nothing is uploaded.
Free to use. Works in your browser. No signup, no login.