---
modificationDate: January 22, 2026
title: Barometer
description: A library that provides access to device's barometer sensor.
sourceCodeUrl: 'https://github.com/expo/expo/tree/main/packages/expo-sensors'
packageName: 'expo-sensors'
iconUrl: '/static/images/packages/expo-sensors.png'
platforms: ['android', 'ios*', 'expo-go']
---

<AgentInstructions>

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</AgentInstructions>

# Expo Barometer

A library that provides access to device's barometer sensor.
Android, iOS (device only), Included in Expo Go

> For the complete documentation index, see [llms.txt](/llms.txt). Use this file to discover all available pages.

`Barometer` from `expo-sensors` provides access to the device barometer sensor to respond to changes in air pressure, which is measured in hectopascals (`hPa`).

## Installation

```sh
npx expo install expo-sensors
```

If you are installing this in an [existing React Native app](/bare/overview), make sure to [install `expo`](/bare/installing-expo-modules) in your project.

## Usage

```jsx
import { useState } from 'react';
import { StyleSheet, Text, TouchableOpacity, View, Platform } from 'react-native';
import { Barometer } from 'expo-sensors';

export default function App() {
  const [{ pressure, relativeAltitude }, setData] = useState({ pressure: 0, relativeAltitude: 0 });
  const [subscription, setSubscription] = useState(null);

  const toggleListener = () => {
    subscription ? unsubscribe() : subscribe();
  };

  const subscribe = () => {
    setSubscription(Barometer.addListener(setData));
  };

  const unsubscribe = () => {
    subscription && subscription.remove();
    setSubscription(null);
  };

  return (
    <View style={styles.wrapper}>
      <Text>Barometer: Listener {subscription ? 'ACTIVE' : 'INACTIVE'}</Text>
      <Text>Pressure: {pressure} hPa</Text>
      <Text>
        Relative Altitude:{' '}
        {Platform.OS === 'ios' ? `${relativeAltitude} m` : `Only available on iOS`}
      </Text>
      <TouchableOpacity onPress={toggleListener} style={styles.button}>
        <Text>Toggle listener</Text>
      </TouchableOpacity>
    </View>
  );
}

const styles = StyleSheet.create({
  button: {
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#eee',
    padding: 10,
    marginTop: 15,
  },
  wrapper: {
    flex: 1,
    alignItems: 'stretch',
    justifyContent: 'center',
    paddingHorizontal: 20,
  },
});
```

## API

```js
import { Barometer } from 'expo-sensors';
```

## Classes

### `Barometer`

Supported platforms: Android, iOS.

Type: Class extends [DeviceSensor](/versions/latest/sdk/sensors)<[BarometerMeasurement](#barometermeasurement)\>

Barometer Methods

### `addListener(listener)`

Supported platforms: Android, iOS.

| Parameter | Type | Description |
| --- | --- | --- |
| `listener` | Listener<[BarometerMeasurement](#barometermeasurement)\> | A callback that is invoked when a barometer update is available. When invoked, the listener is provided with a single argument that is `BarometerMeasurement`. |

  

Subscribe for updates to the barometer.

Returns: `EventSubscription`

A subscription that you can call `remove()` on when you would like to unsubscribe the listener.

Example

```ts
const subscription = Barometer.addListener(({ pressure, relativeAltitude }) => {
  console.log({ pressure, relativeAltitude });
});
```

### `getListenerCount()`

Supported platforms: Android, iOS.

Returns the registered listeners count.

Returns: `number`

### `getPermissionsAsync()`

Supported platforms: Android, iOS.

Checks user's permissions for accessing sensor.

Returns: `Promise<permissionresponse>`

### `hasListeners()`

Supported platforms: Android, iOS.

Returns boolean which signifies if sensor has any listeners registered.

Returns: `boolean`

### `isAvailableAsync()`

Supported platforms: Android, iOS.

> You should always check the sensor availability before attempting to use it.

Check the availability of the device barometer. Requires at least Android 2.3 (API Level 9) and iOS 8.

Returns: `Promise<boolean>`

A promise that resolves to a `boolean` denoting the availability of the sensor.

### `removeAllListeners()`

Supported platforms: Android, iOS.

Removes all registered listeners.

Returns: `void`

> **Deprecated:** use subscription.remove() instead.

### `removeSubscription(subscription)`

Supported platforms: Android, iOS.

| Parameter | Type |
| --- | --- |
| `subscription` | `EventSubscription` |

  

Returns: `void`

### `requestPermissionsAsync()`

Supported platforms: Android, iOS.

Asks the user to grant permissions for accessing sensor.

Returns: `Promise<permissionresponse>`

### `setUpdateInterval(intervalMs)`

Supported platforms: Android, iOS.

| Parameter | Type | Description |
| --- | --- | --- |
| `intervalMs` | `number` | Desired interval in milliseconds between sensor updates. Starting from Android 12 (API level 31), the system has a 200Hz limit for each sensor updates. |

  

Set the sensor update interval.

Returns: `void`

## Interfaces

### `Subscription`

Supported platforms: Android, iOS.

A subscription object that allows to conveniently remove an event listener from the emitter.

Subscription Methods

### `remove()`

Supported platforms: Android, iOS.

Removes an event listener for which the subscription has been created. After calling this function, the listener will no longer receive any events from the emitter.

Returns: `void`

## Types

### `BarometerMeasurement`

Supported platforms: Android, iOS.

The altitude data returned from the native sensors.

| Property | Type | Description |
| --- | --- | --- |
| pressure | `number` | Measurement in hectopascals (`hPa`). |
| relativeAltitude(optional) | `number` | Supported platforms: iOS. Measurement in meters (`m`). |
| timestamp | `number` | Timestamp of the measurement in seconds. |

### `PermissionExpiration`

Supported platforms: Android, iOS.

Literal Type: `union`

Permission expiration time. Currently, all permissions are granted permanently.

Acceptable values are: `'never'` | `number`

### `PermissionResponse`

Supported platforms: Android, iOS.

An object obtained by permissions get and request functions.

| Property | Type | Description |
| --- | --- | --- |
| canAskAgain | `boolean` | Indicates if user can be asked again for specific permission. If not, one should be directed to the Settings app in order to enable/disable the permission. |
| expires | `PermissionExpiration` | Determines time when the permission expires. |
| granted | `boolean` | A convenience boolean that indicates if the permission is granted. |
| status | `PermissionStatus` | Determines the status of the permission. |

## Enums

### `PermissionStatus`

Supported platforms: Android, iOS.

#### `DENIED`

`PermissionStatus.DENIED = "denied"`

User has denied the permission.

#### `GRANTED`

`PermissionStatus.GRANTED = "granted"`

User has granted the permission.

#### `UNDETERMINED`

`PermissionStatus.UNDETERMINED = "undetermined"`

User hasn't granted or denied the permission yet.

## Units and providers

| OS | Units | Provider | Description |
| --- | --- | --- | --- |
| iOS | _`hPa`_ | [`CMAltimeter`](https://developer.apple.com/documentation/coremotion/cmaltimeter) | Altitude events reflect the change in the current altitude, not the absolute altitude. |
| Android | _`hPa`_ | [`Sensor.TYPE_PRESSURE`](https://developer.android.com/reference/android/hardware/Sensor#TYPE_PRESSURE) | Monitoring air pressure changes. |
| Web | ✗ | ✗ | This sensor is not available on the web and cannot be accessed. An `UnavailabilityError` will be thrown if you attempt to get data. |