NIOSH Sound Level Meter vs OpeNoise
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
NIOSH Sound Level Meter
This free app measures sound levels and noise exposure using your smartphone. Developed by acoustics experts, it provides professional-grade metrics and guidance on hearing protection and noise prevention.
- Sound level measurement
- Noise dosimetry
- Hearing hazard information
- Hearing protector guidelines
- Data reporting and sharing
- Microphone calibration
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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
OpeNoise
This application measures real-time sound pressure levels, displaying minimum and maximum values. It offers advanced analysis like third octave and FFT, with options to save data, calibrate, and share measurements with a community. Note: it is not intended for professional use.
- Real-time A-weighted sound pressure level measurement
- Minimum and maximum level tracking
- Third octave and FFT analysis
- Data saving in text file
- Calibration functionality
- Measurements displayed on a map
- Community sharing of calibration and measurements
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OpeNoise is a real-time noise level meter. TECHNICAL SPECIFICATIONS: - Real-time A-weighted sound pressure level measurement - Minimum and maximum level - Third octave and FFT analysis - Data saving in text file - Calibration - Displaying measurements on a map - Metadata compilation - Sharing calibration and measurements with the OpeNoise community TERM OF USE This app is not intended for professional use, it does not necessarily guarantee an accurate noise measurement. Since each device has a different response to noise, a comparison with a professional noise level meter in the measurement dynamic range is required. The utilization of the app requires adequate technical knowledge and skill; an extemporary measurement might not be correct. The calibrations and measurements sent to the OpeNoise community will be used for statistical purposes only and cannot be used in any way to verify compliance with legal limits. CREDITS Developers: Arpa Piemonte (Regional Agency for the Protection of the Environment of Piedmont - Italy - www.arpa.piemonte.it). The code is open source under GNU v.2 license or later, the code is on GitHub: https://github.com/Arpapiemonte/ KEYWORDS noise level meter, level, sound, noise, measure, measurement, dB, db, dBA, dB(A), decibel
Screenshots
Verdict
The clearest difference is rating: NIOSH Sound Level Meter at 4.7 against OpeNoise's 4.0. NIOSH Sound Level Meter also leads on ratings volume (17K vs 4). OpeNoise's advantage is review sentiment (86% vs 64%). On price, update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
NIOSH Sound Level Meter holds the better App Store score, 4.7 against 4.0. That said, the two scores are not equally well evidenced: NIOSH Sound Level Meter has 17K ratings behind it against 4, so its average is the more settled of the two. Written reviews complicate that: 64% of NIOSH Sound Level Meter's written reviews are positive against 86% of OpeNoise's, so the app with the better star average is not the one people write more warmly about.
NIOSH Sound Level Meter ships an update every 4 months, OpeNoise every 7 months. The most recent releases landed on September 24, 2026 and September 21, 2026 respectively.
| Parameter | NIOSH Sound Level Meter | OpeNoise |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (17K ratings) — better | 4.0 (4 ratings) |
| Positive reviews | 64.5% of reviews | 85.7% of reviews — better |
| Number of ratings | 17K — better | 4 |
| Update frequency | Every 4 months — better | Every 7 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 15.0 | 14.0 — better |
| Further details — not scored | ||
| Size | 6 MB | 18 MB |
| Age rating | 4+ | 4+ |
| Developer | EA LAB | Arpa Piemonte |
Customer experience
NIOSH Sound Level Meter
OpeNoise
Bugs and requests
NIOSH Sound Level Meter
Reported bugs
3 issues- Inconsistent or inaccurate readings in some cases
- Inability to properly connect and use external microphones
- Freezing or crashing when minimizing the app
Requested features
4 requests- Ability to save and export measurement sessions
- Option to run the app in the background while the screen is locked
- Integration with Apple Health for long-term noise exposure tracking
- Frequency-specific noise measurements (e.g., A-weighted, C-weighted)
OpeNoise
Not enough reviews yet to summarise bugs or requests.
In-app purchases
NIOSH Sound Level Meter
No in-app purchases
OpeNoise
No in-app purchases
Questions
Is NIOSH Sound Level Meter free?
Is OpeNoise free?
Which has better reviews, NIOSH Sound Level Meter or OpeNoise?
Do NIOSH Sound Level Meter or OpeNoise have ads?
Which is updated more often, NIOSH Sound Level Meter or OpeNoise?
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