Emergencies are, by definition, unexpected, so it’s critical to know exactly how your phone can help when you need it most. Both iOS and Android have built-in capabilities that will almost instantly alert first responders, family, and friends to the fact that you need assistance.

If you fear pocket-dialing the paramedics, you can limit these settings, but you can’t shut them off entirely—federal law requires all phones sold in the US to be able to dial 911, whether or not they have an active SIM card or are linked to the available wireless networks. As long as your device can make some sort of connection, you should be able to call for aid.

Emergency call settings on iPhones

The fastest way to call emergency services on an iPhone is to use Emergency SOS. Fully enabled, you’ll be able to notify first responders without taking your device out of your pocket or bag—as long as you can grab your phone, you can fire off a cellular flare.

By default, an iPhone 8 or later model will call for help if you hold down the side button and either volume button. Do this, and the Emergency SOS slider will appear within seconds. Then, you can drag it to the right to make the call, or keep holding to activate a five-second countdown before the call goes out. You cannot turn this off. During the countdown, your phone will vibrate to let you know it’s working. Stop the countdown at any time by releasing the buttons.

On all iPhone models, you can rapidly press the side or top button five times to do the same thing (except in India, where it’s three times). While this setting is default on any iPhone 7 or earlier model, you can turn it off on newer devices by opening the Settings app, finding Emergency SOS, and toggling off the Call with Side Button switch. If you do use it, you have to press it quickly or it won’t work. This method starts a three-second countdown before the call goes out, and will activate a loud alarm even if your phone volume is completely off. The only way to prevent the siren is to toggle off the Countdown Sound switch within the Emergency SOS settings. Cancel a call by tapping the Stop button and confirming that you want to Stop Calling.

There’s also an Auto Call toggle switch within the Emergency SOS settings. When on, your phone will automatically dial the local emergency number once its countdown ends. If you turn it off, you can still use the slider to force the call, but your phone won’t make calls on its own. This could help if you’re prone to accidentally activating the emergency call features, but it won’t help if you can’t interact with your phone. This feature also requires a SIM card and you might still need to specify an emergency service in some areas, Apple says.

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You can manage your emergency contacts within the Emergency SOS settings by tapping Edit Emergency Contacts in Health, which will take you to Apple’s built-in Health app. There, hit Edit in the top right and scroll down to add emergency contact. After any emergency call ends, your phone will text these contacts about your situation unless you choose to cancel the message. Your device will also send them your location and update them when your location changes, even if location services is off.

No matter which Emergency SOS shortcut you use, your phone will disable biometrics like Touch ID until you enter your passcode, even if you cancel the call. This prevents anyone from using your fingerprint or face to open your phone.

You can also dial for aid by activating the lock screen, tapping Emergency and dialing 911 or another emergency number.

Emergency call settings on Android phones

The emergency call settings built into Android phones may differ depending on your device’s manufacturer, but Google includes its Personal Safety app on stock Android handsets and other users can grab it for free from the Google Play store.

If you’ve set a lock screen on your device, the passcode entry screen will have an emergency call button at the bottom. You or anyone else will be able to dial 911 from this screen, whether it does so automatically or requires you to plug in the number manually.

Your phone may also send your location to first responders during an emergency call or text, if you have Android Emergency Location Service on and it’s available in the country you’re in. To manage this feature, open the Settings app, tap Location or Security & location, and then hit Location. Next, go to Advanced > Emergency Location Service or Google Emergency Location Service and turn it on or off.

Don’t stop there

No matter which operating system you use, make sure you take some time to learn the safety features built into various apps once you’ve got the built-in settings set up the way you like them. Then, consider downloading some other apps that may help with specific emergencies. You can never be too prepared.