NRR Attenuation Calculator

Unfortunately, due to the way that attenuation ratings are calculated, the real-world performance of your hearing protection is likely to be different from the laboratory-tested performance.

To help you determine how much protection you’ll need to protect your hearing, we’ve created a calculator that reduces the attenuation to more realistic levels based on OSHA’s formula.

Our calculator will tell you the estimated dB(A) noise exposure whilst hearing protection based on the NRR of the hearing protection. It’s extremely important to remember that when you’re determining noise exposure, you should be working with a time-weighted average, not just a single measurement. This means you should try to determine the average noise level over the course of the day rather than just measuring it at a single moment.

This calculator only works with the NRR attenuation rating system, not SNR. If you’re interested in the differences, check out our article that explains them both.


Reduced Noise Level:

0 dB

dB(A) vs dB(C)

Depending on the tool you’re using to measure volume with, you’re likely to have a number that’s either dB(A)-weighted or dB(C)-weighted. The differences are important, as it determines how the attenuation reduction should be done. Luckily for you, our calculator supports both. Other decibel weighting systems exist, but they’re less common.


If you’re in the workplace, dB(A) is the weighting system you’re most likely to work with. This system attempts to weight the volume based on the sensitivity of the human ear to different frequencies. This means that the low frequencies don’t count so much towards the output decibel reading. As a result, this system is believed to be far more useful for determining the actual risk of hearing loss in a noise environment.


This system isn’t used as commonly in the workplace as dB(A). This is because dB(C) doesn’t weight the measurement based on frequency nearly as much as dB(A). A dB(C) measurement is very similar to an unweighted decibel reading with a small amount of weighting applied to low and high frequencies.