New NIOSH Sound Level Meter App

February 21, 2017

NIOSH has released a new sound level meter app for iOS devices that can help those on construction sites and operating heavy equipment monitor their exposure to hearing disablers.

The app marketplaces have many noise level measuring programs for smartphones but NIOSH testing found variables such as the device's microphone location (internal or external) and the microphone's physical configuration affected the accuracy of the readouts. Additionally, the software features in each app spanned a broad range of simple decibel visuals to detailed data interpretations.

Given how important occupational sound levels are to worker safety and quality of life, NIOSH has released its own free NIOSH Sound Level Meter (NIOSH SLM) app for iOS devices available on iTunes .


  • Raises workers’ awareness about their work environment
  • Helps workers make informed decisions about the potential hazards to their hearing
  • Serves as a research tool to collect noise exposure data
  • Promotes better hearing health and prevention efforts
  • Easy to use

The NIOSH SLM app has many important features and provides a readout of the sound level using the built-in microphone (or external microphone if desired) and will report instantaneous sound levels in A, C, or Z-weighted decibels.

The app was subjected to the same testing requirements that were established in the NIOSH laboratory study.  It met the testing criteria (± 2 dB mean difference from the reference type 1 sound level meter). 

The NIOSH SLM app, when used with an external calibrated microphone, measured sound levels within ± 1 dB of the reference SLM over the testing range of 65 -95 dB SPL in the laboratory.  While the app is not meant to replace a professional sound level meter or a noise dosimeter or be used for compliance purposes, the app can help workers make accurate noise measurements and adjust their exposure with the use of hearing protection devices.

Click here for NIOSH's Noise and Hearing Loss Prevention resource page.