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Audio Frequency Fatigue Calculator

Enter a sound level in dBA to see the maximum safe listening time under the NIOSH and OSHA exposure standards, with a risk rating — plus why the 2–5 kHz range drives listening fatigue.

Educational, not a substitute for a real measurement or medical advice. A browser can’t measure your actual exposure — enter a level you measured (e.g. with a calibrated meter or our Decibel Meter as a rough guide). The safe-time figures use the official NIOSH/OSHA formulas, but real risk depends on your true dose. If you have ringing, muffling or any hearing concern, see an audiologist.

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NIOSH safe time
85 dBA = 8 h, 3 dB rule
OSHA safe time
90 dBA = 8 h, 5 dB rule

Reference: levels & NIOSH safe time

Exposure & the Fatigue Zone

Safe exposure time comes from occupational standards. NIOSH recommends a limit of 85 dBA for 8 hours with a 3 dB exchange rate — every 3 dB louder halves the safe time (88 dBA → 4 h, 91 → 2 h, 100 → 15 min). OSHA’s legal limit is more lenient: 90 dBA for 8 hours with a 5 dB exchange rate. This calculator applies those exact formulas, so you can see how quickly safe time shrinks as level rises.

Listening fatigue is different from hearing damage — it’s the tiredness and irritation that builds up well below dangerous levels, and it concentrates in the 2–5 kHz region. That’s no accident: the ear canal resonates around 3 kHz, making us most sensitive there, so harshness, sibilance and cymbal/edge energy in that band feel fatiguing fastest. Taming 2–5 kHz, keeping levels moderate, and taking regular breaks all reduce fatigue.

Reducing fatigue and protecting your hearing

  • Keep everyday listening well below 85 dBA where you can; the quieter, the longer it’s safe.
  • Take breaks — the "60/60" idea (≤60% volume, ≤60 minutes, then rest) is a simple habit.
  • For sustained loud environments (concerts, power tools), wear hearing protection.
  • If a mix feels harsh or tiring, look first at the 2–5 kHz range rather than just turning everything down.

Frequently Asked Questions

Why do NIOSH and OSHA give different times?
They use different reference levels and exchange rates. NIOSH (85 dBA, 3 dB) is more protective and reflects current hearing-science consensus; OSHA (90 dBA, 5 dB) is the older US legal limit. NIOSH will almost always show a shorter, safer time.
What is the 2–5 kHz fatigue zone?
The frequency range our hearing is most sensitive to, largely because the ear canal resonates near 3 kHz. Excess energy there — harsh vocals, sibilance, cymbals, distortion edge — causes listening fatigue quickly, even at moderate volumes.
How do I know my dBA level?
Measure it with a calibrated sound-level meter or a phone SPL app for a rough idea. A browser mic isn’t calibrated, so enter a measured figure here rather than guessing — the safe-time math is only as good as the level you put in.
Is listening fatigue the same as hearing damage?
No. Fatigue is temporary tiredness/irritation that can happen at safe levels; damage is permanent and comes from loud and/or prolonged exposure. Both are worth avoiding — fatigue by managing tone and breaks, damage by respecting the safe-time limits.
Does this measure or process audio?
No. It only calculates from the dBA level you enter. For a live (uncalibrated) level reading, see our Decibel Meter.