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Decibel Sound Meter

Does iPhone have a decibel meter? Not one for the room you're in

No: iOS has no built-in app that measures the noise around you, and the level you can add to Control Center only shows what plays through your headphones. To read room noise in decibels you need a sound meter app, which uses the same microphone the iPhone already has.

4 min read · Updated 2026-09-17

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Adding the Hearing control to Control Center shows a dB bar that can look like a room meter at first glance. Unplug the headphones, though, and the bar has nothing to show. It measures what goes into your ears through headphones, not the room.

What Apple actually gives you

Sound levels you can already see on Apple devices
WhereWhat it measuresRoom noise on iPhone alone?
Hearing control in Control CenterLive level of audio playing through connected headphonesNo
Health app, Headphone Audio LevelsHistory of that same headphone audioNo
Health app, Environmental Sound LevelsRoom noise, but the readings come from an Apple WatchOnly if you wear a watch
Voice MemosRecords sound; shows a waveform, no decibel numberNo

Same story on an iPhone 14, 15 or 16: the mic hears the room just fine. Apple just never turns that into a number on the phone itself.

Where is the decibel meter on iPhone, then?

In an app. In Decibel Sound Meter it's the first tab, Meter, with the screen title Sound Meter. There is no start button to find: the number moves as soon as the microphone is allowed.

  1. Install the app and open it. The home-screen icon is called Sound-Meter.
  2. On Microphone Access Required, tap Continue, then allow the microphone in the iOS prompt. A second prompt asks about tracking for ads; saying no changes nothing in the readings.
  3. Read the big number. It's A-weighted, so it follows how ears hear, and it uses a Fast response that reaches 90% of a new level in 0.29 seconds.
  4. Under it you'll see Peak, the highest recent level held for 2 seconds, and a word such as Conversational or Loud.
  5. For a figure worth writing down, tap Start Recording, wait 30 to 60 seconds, then Stop Recording and Stop & Save. AVG is the one to quote.

Preview Mode at the bottom toggles the live reading. If the screen shows --, a phone call has the microphone; it comes back on its own.

How accurate is it on an iPhone?

Good enough to tell one room is louder than the next, or to catch a TV that's creeping up. Not lab-grade, and the app doesn't pretend otherwise: right on the main screen it says A-weighted estimate — a phone is not a certified sound level meter.

Phone microphones read low, so the app adds a built-in correction before it shows anything: +10 dB on iPhone, +8 dB on iPad. If you can borrow a real sound level meter for five minutes, you can replace the guess with a measured offset. Here is what that looked like with numbers:

Worked example: default offset, then matching a reference meter
StepValueWhat the app shows
Microphone level before any correction40 dBNothing yet
Built-in correction, iPhone (iPad)+10 dB (+8 dB)50 on iPhone, 48 on iPad
Reference meter beside the phone, steady fan noise47.2 dBiPhone still shows 50
Difference entered as Calibration offset47.2 - 50 = -2.8 dBSlider set to -2.8
Same fan after calibrating50 - 2.8 = 47.2 dBMeter shows 47; SPL now in Exposure shows 47.2

That slider lives in the Exposure tab under Calibration (Match a reference meter). It goes from -15 to +15 dB in 0.1 dB steps, has a Live reading so you can watch it settle, and applies to every reading in the app, not just that tab.

Sharp sounds are a known weak point: a clap a few centimetres from the microphone can make Peak come back lower than a clap that close should be. Phone microphones squash short bangs, and no offset fixes that.

What it can't do, and what's free

  • Only A-weighting with a Fast response: no C or Z weighting, no Slow, no frequency bands.
  • It can't read the volume inside your headphones; for that, Apple's Hearing control is the right tool.
  • No Apple Watch app and no widgets; it runs on iPhone and iPad with iOS 17 or later.
  • Free: the live meter, recordings with MIN, AVG and MAX, History, calibration and the whole Exposure tab, with ads.
  • Premium removes the ads and adds things like unlimited PDF and CSV exports, the Noise Map and alerts at your own threshold. The exports are the feature most worth paying for; the number itself is free either way.

Questions and answers

Does iPhone 16 have a decibel meter?
Not for room noise, same as the iPhone 14 and 15. Its microphone can hear the room, but iOS only shows decibels for headphone audio, in the Hearing control and the Health app. A sound meter app such as Decibel Sound Meter adds the room reading; it runs on any iPhone with iOS 17 or later.
Does iOS have a decibel meter for environmental noise?
Only through an Apple Watch: the Health app's Environmental Sound Levels are recorded by the watch, not by the iPhone. Without a watch, you need an app that reads the iPhone's own microphone.
Do iPhone decibel meters work?
Yes, for everyday checks. Expect a few decibels of difference from a professional meter unless you calibrate against one, and expect short bangs to read low. They are good for comparing places and spotting when something is clearly loud.
Is there a free decibel meter for iPhone?
Decibel Sound Meter is free to download, and the live meter, recordings, calibration and the NIOSH/OSHA Exposure tab cost nothing. The free version shows ads; Premium removes them and adds extra exports and tools.

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