Decibel Shield
Can an Android phone measure decibels? How to use it as a decibel meter
Yes, as an estimate. An Android phone can show roughly how loud a place is, but readings vary more from one Android model to the next than between iPhones: in a study of 100 phones, Android apps read about 7.5 dB low at 90 dB(A). Use it to compare and screen, and check it against a known level.
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What does the research say about Android phones?
Two studies are worth knowing.
NIOSH, 2014. Researchers at the US National Institute for Occupational Safety and Health looked at 62 Android sound meter apps and found that only 4 partly met their criteria for testing, against 10 of more than 130 iOS apps (Kardous & Shaw, JASA 2014). In limited testing on four Android phones, the same app gave widely different readings on different devices. NIOSH published accuracy figures for iPhone apps only, so any claim that “NIOSH found Android apps off by X dB” has no source (follow-up study, JASA 2016).
Murphy and King, 2016. This is the study with Android numbers. The authors ran 1,472 tests on 100 phones (65 iPhones and 35 Android phones covering 18 Android models) with seven apps, in a test room at four sound levels (Applied Acoustics 106, 2016; open copy). Across all tests the Android apps read 2.79 dB(A) low on average and the iPhone apps 2.93 dB(A) high. The averages hide the real difference, which is spread: Android readings scattered more (a standard deviation of 9.58 dB against 6.81 for iPhones).
| True level in the room | iPhones read, on average | Android phones read, on average |
|---|---|---|
| 27 dB(A) (quiet room) | 35.4 dB(A) | 24.2 dB(A) |
| 50 dB(A) | 53.4 dB(A) | 48.3 dB(A) |
| 70 dB(A) | 71.3 dB(A) | 70.9 dB(A) |
| 90 dB(A) | 88.0 dB(A) | 82.5 dB(A) |
The row to remember is the last one: at 90 dB(A), a level that matters for hearing, the Android phones read about 7.5 dB low. A later test of ten phones found the same thing, with Android apps consistently under-reporting at 90 dBA (McLennon et al., J Occup Environ Hyg 2019).
Why do Android phones differ so much?
Because “Android” is thousands of different devices. NIOSH gives this as the reason its own sound level meter app exists only for iPhone: Android phones come from many manufacturers with different microphones, audio chips and software, so the agency cannot verify one app’s accuracy across them in its laboratory (NIOSH Sound Level Meter app).
Android’s own rules leave room for it. The document every certified Android device must follow requires automatic gain control and noise reduction to be off by default on one microphone source (the one meant for voice recognition), but how many digital units a given sound level produces is only a recommendation (a 1,000 Hz tone at 90 dB SPL “should” give a set value), and the fully unprocessed microphone source is optional (Android Compatibility Definition, audio recording; unprocessed audio). So two phones can both pass and still report different numbers for the same sound.
Does Android have a built-in decibel meter?
Android itself does not come with a sound meter app. Samsung has added a Hearing feature to Samsung Health that uses a compatible Galaxy Watch to monitor the sound level around you and alert you to loud exposure; Samsung’s support page names the Galaxy Watch9 and Galaxy Watch Ultra2 (Samsung support). On the phone, you need an app or a web page that reads the microphone.
How do I measure decibels on an Android phone for free?
In Chrome, with nothing to install:
- Open the free online decibel meter in Chrome.
- Press Start and choose “Allow while visiting the site” (or “Allow this time”) when Chrome asks for the microphone. Chrome lets a site use the microphone only while you are on its tab (Chrome Help).
- Read the level around you, with the minimum, average and maximum of the session and the NIOSH safe time for that level. Nothing is recorded or uploaded.
To keep it on your home screen, use the Install button the meter shows when Chrome offers it, or Chrome’s menu, which has an install option for web apps (Chrome Help: use web apps). It then opens like any other app.
The meter’s reading is an uncalibrated estimate, within about ±10 dB; see how accurate the online meter is.
How do I get a better reading on Android?
- Check it against a known level. If you can stand next to a calibrated sound level meter, note the difference and correct for it with the meter’s calibration control. That corrects the offset of your phone at that level.
- Expect loud sound to read low. In the tests above, Android phones under-read at 90 dB(A), so treat a loud reading as a floor.
- Read the average, not the jumping number. Hearing limits are set on average exposure over time. See what dB(A) means.
- Keep the microphone clear. Take off a thick case and keep fingers off the microphone opening.
- Consider an external microphone. With calibrated external microphones, NIOSH measured iPhone apps within ±1 dB of its reference. The authors expected a similar gain on Android and did not test it. See external microphones for phone measurements.
Is an Android phone accurate enough for a noise complaint or for work?
For your own awareness, yes. As evidence, no. Anything legal or occupational needs a calibrated meter that meets IEC 61672; see phone apps against dedicated SPL meters. A phone log is still useful for showing a pattern of dates and times: see measuring noise for a complaint.
Is an iPhone more accurate than an Android phone?
More consistent, in the tests so far. Apple ships a few models with tightly controlled microphones, so an app can carry a correction for each one, and the best iOS apps NIOSH tested read within about ±2 dB of its reference. In the 100-phone study, only one app, on iPhone, stayed within ±2 dB(A) at all four levels. If you have both, read can your iPhone measure decibels?
