Noise is a new app for the Apple Watch. It was introduced as part of the 2019 OS update; if you install watchOS 6, or buy a device that has it preinstalled, you'll find Noise in the app list without having to take any further action.

Noise is quite descriptively named: its job is to listen to the ambient noise levels and tell you if and when they become harmful to your hearing. You only get one pair of ears, you know.

In this tutorial we explain how to use the Noise app on your watch to measure how loud it is wherever you are, and to receive notification warnings when noise levels become excessive.

How to measure the ambient noise levels

Go to your apps screen by pressing the Digital Crown, then locate and tap the Noise icon. For those in grid view, it's a yellow circle with an ear on it.

How to use Noise on Apple Watch: OK

You'll now see Noise's default - and pretty much only - interface screen. The current noise level, measured in decibels (dB), is displayed at the top; at the bottom you get a colour-coded verdict on whether that level is dangerous to your hearing.

How to use Noise on Apple Watch: Loud

You can click this verdict/warning for a little more information, including how long you would need to be exposed to each noise level to damage your hearing.

How to set up notifications

Noise is essentially a passive app: by default it listens out all the time. This means that instead of having to actively open the app and take a reading, you can simply have it send you a notification when things get too noisy.

Open the Watch app on your companion iPhone and, from the default My Watch tab, scroll down and tap Noise. (Alternatively you can tap Notifications > Noise; this will take you to the same screen.)

How to use Noise app on Apple Watch: Notification settings

Tap Noise Threshold to set the number of decibels that will trigger a notification: you can choose 80, 85, 90, 95 or 100dB. In each case the notification will be sent only if the level is sustained across three minutes or more; a single loud spike won't trigger it - and of course a notification would be no use in that case anyway, since any damage would have been done.

Above the Noise Threshold setting, you'll see the option to toggle off Environmental Sound Measurements, which is what makes Noise listen out throughout the day. Doing so would likely save some battery life, but you'd be back in the situation where you have to open the app manually every time you want to measure the loudness.

How to set up a Noise complication

If noise measurement is a priority for you, we recommend setting up a complication on your watch face. This means you'll be able to glance at your watch at any time and instantly see a real-time measurement of the ambient noise level.

Different watch faces allow differing numbers of complications (a few do not allow any); if you don't want to sacrifice any of your current complications you may have to select a different face that allows more.

Do a hard press on the screen and tap Customise. Swipe right to get to the complications, tap the complication you want to change, and then scroll through until you get to Noise - they're arranged alphabetically.

How to use Noise app on Apple Watch: Set up a complication

Note that, depending on the size of the complication slot which you've assigned to Noise, you'll see differing amounts of information.

How to use Noise app on Apple Watch: Modular Compact face

The Modular Compact face (above), new in watchOS 6, by default has a large Noise complication with a colour-coded horizontal 'equaliser'. Smaller complications may only show the decibel figure and whether this is okay or loud, or even just the bare number. But in any case you'll be able to tap the complication to open the app and get more information.

And there you go: that's everything you need to know about the Noise app. Remember that you need to have installed watchOS 6 to use Noise. And for more advice, see How to use the Apple Watch.