# General Translation Platform: standardizeLocale
URL: https://generaltranslation.com/en-GB/docs/platform/core/reference/utility-functions/locales/standardize-locale.mdx
---

title: standardizeLocale
description: Normalise a locale code into a standard format without a GT instance. API reference for standardizeLocale.

---

[`standardizeLocale`](/docs/platform/core/reference/gt-class-methods/locales/standardize-locale) is a standalone utility function from General Translation's Core library that normalises a BCP-47 locale code into its canonical form, correcting casing.

## Overview [#overview]

Import `standardizeLocale` directly from `generaltranslation` and call it with a locale code. It does not require an API key or a [GT](/docs/platform/core/reference/gt-class/constructor) instance. For the instance-based equivalent, use the [`standardizeLocale`](/docs/platform/core/reference/gt-class-methods/locales/standardize-locale) method on a [`GT`](/docs/platform/core/reference/gt-class/constructor) instance instead.

```typescript
import { standardizeLocale } from 'generaltranslation';

// Normalise casing
console.log(standardizeLocale('EN-gb')); // 'en-GB'
console.log(standardizeLocale('fr-ca')); // 'fr-CA'

// Already standardised locales pass through
console.log(standardizeLocale('es-ES')); // 'es-ES'
```

Signature:

```typescript
standardizeLocale(locale: string): string
```

## How it works [#how-it-works]

* **Canonicalisation.** Passes the input to `Intl.getCanonicalLocales` and returns the first canonical result, which normalises casing (language lowercase, region uppercase, script title case).
* **Fallback.** If the input cannot be canonicalised, the original input string is returned unchanged.

## Parameters [#parameters]

| Parameter           | Description                            | Type     | Optional | Default |
| ------------------- | -------------------------------------- | -------- | -------- | ------- |
| [`locale`](#locale) | The BCP-47 locale code to standardise. | `string` | No       | —       |

### `locale` [#locale]

**Type** `string` · **Required**

The BCP-47 locale code to standardise.

## Returns [#returns]

**Type** `string`

The standardised BCP-47 locale code, or the input string unchanged if it cannot be standardised.

## Examples [#examples]

```typescript
import { standardizeLocale } from 'generaltranslation';

// Normalises casing on hyphenated tags
console.log(standardizeLocale('EN-gb')); // 'en-GB'
console.log(standardizeLocale('fr-ca')); // 'fr-CA'
console.log(standardizeLocale('en-us')); // 'en-US'

// Already standardised locales pass through
console.log(standardizeLocale('es-ES')); // 'es-ES'

// Non-canonicalisable input is returned unchanged
console.log(standardizeLocale('en_us')); // 'en_us' (underscore is not valid BCP-47)
console.log(standardizeLocale('not a locale')); // 'not a locale'
```

```typescript
import { standardizeLocale, isValidLocale } from 'generaltranslation';

// Normalising user input
function processUserInput(input: string) {
  const standardized = standardizeLocale(input.trim());
  const isValid = isValidLocale(standardized);

  return {
    original: input,
    standardized,
    isValid,
  };
}

// Test various inputs
const inputs = ['EN-gb', 'FR-ca', 'invalid', 'zh-CN'];
inputs.forEach((input) => {
  console.log(processUserInput(input));
});
```

## Notes [#notes]

* Normalises casing (language lowercase, region uppercase) via `Intl.getCanonicalLocales`.
* Returns the input string unchanged for inputs that cannot be canonicalised.
* Essential for normalising locale input from various sources.
* No external dependencies beyond the `Intl` API.