US · USA

United States languages and locale codes

Official or primary languages with practical BCP 47 locale recommendations.

BCP 47

Languages and locale codes

Language	Code	Recommended locale	Status
English			Official
Spanish			Regional official
Hawaiian			Regional official

Use U.S. language and region labels precisely

USAGov states that English was designated the official language of the United States by a March 2025 executive order. The Spanish and Hawaiian rows describe regional status in the bundled CLDR data; they are not additional federal designations.

Use en for content actually written in English and en-US when U.S. regional formatting is intended. A visitor's country still does not determine their preferred language.

// English text: <html lang="en">
new Intl.NumberFormat("en-US").format(1234567.89);

Compare number and date formatting

These examples use 1234567.89 and the fixed instant 2026-01-15T13:45:00Z, with dates displayed in UTC. Intl computes the results when this site is built; your browser and locale-data version may differ. Unsupported tags are identified instead of showing default-language output.

Intl formatting examples (UTC)
Locale	Number	Date	Currency
`en-US`	1,234,567.89	January 15, 2026	USD: $1,234.50
`es-US`	1,234,567.89	15 de enero de 2026	USD: $1,234.50
`haw-US`	1,234,567.89	15 Ianuali 2026	USD: $1,234.50

Currency examples use the fixed value 1234.5. SIX and CLDR snapshot: 2026-09-26. Specify each currency explicitly; formatting is not an exchange rate.

new Intl.NumberFormat("en-US", { style: "currency", currency: "USD" }).format(1234.5);

Before adopting a tag, run Intl.NumberFormat.supportedLocalesOf() and Intl.DateTimeFormat.supportedLocalesOf() in your target runtime. A locale does not select a time zone or translate interface text; specify currency explicitly when formatting money.

Intl locale support reference (MDN)

Data provenance

Sources

Data snapshot: 2026-09-26