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This award-winning app combines the best features of professional sound level meters and noise dosimeters into a simple, easy-to-use package.
- Developed by experienced acoustics engineers and hearing loss experts.
- Completely FREE – No ads, no limited features, and no in-app purchases.
- Tested and validated (accuracy ± 2 dBA) according to standards in a reverberant chamber at NIOSH acoustics lab – the only proper method to validate accuracy.
- Trusted source and world-class expertise in noise and hearing research.
- Meets Type 2 requirements of IEC 61672:3 SLM standard when used w/ external microphone.*
- Provides the most relevant metrics found in professional sound instruments today. Averages such as LAeq and TWA, Max and Peak Levels, Noise Dose and Projected Dose according to NIOSH and OSHA standards, and all three major weighting networks (A, C, and Z).
- Capability to calibrate either internal or external microphone. Reporting and Sharing data.
- Up-to-date informational screens on what noises are considered hazardous, how to conduct a noise measurement, how to properly select a hearing protector, and guidelines for preventing hearing loss, all at the palm of your hand.
- Excellent and timely support from NIOSH hearing experts.
- Support for Apple's Health (Hearing) app.

* Celestina M, Hrovat J, Kardous CA [2018]. Smartphone-based sound level measurement apps: Evaluation of compliance with international sound level meter standards. Applied Acoustics, 139:119-128. https://doi.org/10.1016/j.apacoust.2018.04.011

More resources (including instructional videos and a user manual), a science blog, FAQ, and information about how to interpret results can be found on the NIOSH SLM website https://www.cdc.gov/niosh/topics/noise/app.html

What’s New

Version 1.2.1

This update fixes the screen rotation issue in the newly released major update 1.2.0

Ratings and Reviews

4.7 out of 5
4.4K Ratings

4.4K Ratings

Diray Acosta ,

Doesn’t Work

I was using it to try out the free version and when I installed it and opened the app for the first time; it showed me readings that were very untrue like 120dB. I know this isn’t right because I was lying in my bed with no electronics on next to me or anything loud at all. I don’t know what the problem is since there’s so many positive comments but it no work :(

EDIT: I thought there could be a free version and a paid version but I guess I was wrong. This review is not for a different app by the way, it was just what the app was showing me. But I do not have a professional microphone attached to my iPad so if you want to say it was that I guess it could be 🤔 yet I doubt it. I will change my review to 4 stars because I am only testing this against 3 other decibal meters and not a profesional machine or a sound that is supposed to be at a specific level.

Developer Response ,

We believe this review is for a different app. The reviewer reports trying a "free version" of the app, but that's all there is, there is no paid version or in-app purchasing, the app is completely free. We believe the reviewer is confusing our app with another. The reviewer also reports seeing 120 decibels in his bed, which is virtually impossible for our app.

Disgruntled albatraoz ,

Well done

I have been using this app for over a year and through several updates. It has always worked well and accurately. It has been a useful tool for monitoring the noise exposure and deciding where and when I need to wear earplugs. The only feature it lacks (in my opinion) is the ability to run as a background process with the phone asleep (similar to the way you can play music), which would allow to have the screen off and use less battery when monitoring for long periods of time. Aside from that personal preference, this app has been reliable and helpful. I would highly recommend it.

AcousticsProf ,

The only truly free and most accurate decibel app

No ads, no in-app purchases, no hassle to upgrade every 10 seconds, fully-featured unlike the other top apps that entice you with a single feature but force you buy an upgrade to get the rest of the functionality of the app.

Developed for professional users who are serious about acoustics by the top hearing lab in the country, if not the world. I use a Larson-Davis 831 for my daily work and have compared many apps to my SLM and though I was always skeptical about apps, this one is the most accurate out there.


EA LAB d.o.o.
17.7 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, Spanish

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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