Noise dose calculator
Add up a day’s loud activities and see the total against the NIOSH recommended limit (85 dBA for 8 hours, 3 dB exchange rate) and, for comparison, OSHA’s legal limit (90 dBA, 5 dB). Then see what earplugs or earmuffs would change.
Your day
This calculator needs JavaScript. The rule it applies: every 3 dB above 85 dBA halves the safe time (NIOSH).
NIOSH
OSHA
With hearing protection
Lab ratings assume a perfect fit. Each estimate above is a published way of allowing for real-world fit; see NRR vs SNR.
How the maths works
For each activity, the time you spend is divided by the time allowed at that level, and the fractions are added: 100% is the daily limit. NIOSH allows 8 hours at 85 dBA and halves the time for every 3 dB more (so 15 minutes at 100 dBA). OSHA allows 8 hours at 90 dBA and halves it every 5 dB (2 hours at 100 dBA). NIOSH counts everything from 80 dBA up; OSHA’s limit counts only time at 90 dBA or more. Both were written for working adults: they are a guide for anyone else, not a guarantee of safety. Details and the source tables are in How loud is too loud?