NIOSH Sound Level Meter

NIOSH Sound Level Meter is a free Chrome extension that combines professional sound level meter and noise dosimeter capabilities in a simple, easy-to-use package. Developed by experienced acoustics engineers and hearing loss experts, it brings trusted NIOSH expertise to your fingertips.

Its measurement suite includes LAeq, TWA, Max and Peak Levels, Noise Dose and Projected Dose, with A, C, and Z weighting networks. The app can calibrate internal or external microphones, supports data reporting and sharing, and works with Apple Health (Hearing) app. It is ad-free with no in-app purchases and has been validated for accuracy ±2 dBA in a reverberant chamber at the NIOSH acoustics lab. When used with an external microphone, it meets Type 2 IEC 61672-3 SLM standards. Resources such as instructional videos, a user manual, and a science blog are available on the NIOSH SLM site.