[Home](./index.md) > [@firebase/auth](./auth.md) > [updatePhoneNumber](./auth.updatephonenumber.md)
## updatePhoneNumber() function
Updates the user's phone number.
Signature:
```typescript
export declare function updatePhoneNumber(user: User, credential: PhoneAuthCredential): Promise;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| user | [User](./auth.user.md) | The user. |
| credential | [PhoneAuthCredential](./auth.phoneauthcredential.md) | A credential authenticating the new phone number. |
Returns:
Promise<void>
## Example
```
// 'recaptcha-container' is the ID of an element in the DOM.
const applicationVerifier = new RecaptchaVerifier('recaptcha-container');
const provider = new PhoneAuthProvider(auth);
const verificationId = await provider.verifyPhoneNumber('+16505550101', applicationVerifier);
// Obtain the verificationCode from the user.
const phoneCredential = PhoneAuthProvider.credential(verificationId, verificationCode);
await updatePhoneNumber(user, phoneCredential);
```