Decibel Meter & Noise Exposure
How loud is too loud, and how phone sound meters work
The decibel (dB) scale is logarithmic, not linear — a jump of 10 dB represents roughly a 10x increase in sound intensity, and is perceived by human ears as roughly twice as loud. That's why the difference between a quiet office (around 50 dB) and a rock concert (110 dB or more) sounds so much bigger than the raw numbers suggest.
Most consumer sound-level apps use dB(A) weighting, which adjusts the raw measurement to match how sensitive the human ear actually is at different frequencies — it's the standard used in occupational and public-health noise guidance. NIOSH's commonly cited recommendation is that exposure to 85 dB(A) for more than 8 hours a day carries a meaningful risk of hearing damage over time, with the "safe" exposure time roughly halving for every 3 dB increase above that.
A phone's built-in microphone can give a genuinely useful reading for everyday awareness — a concert, a workshop, a loud commute — but it isn't a calibrated instrument the way a dedicated sound-level meter is, and readings can vary by phone model. We built SoundGauge to turn that everyday reading into something actionable: not just a number, but a running average, a peak, and a plain-English sense of whether the room you're in is worth worrying about.
The app
How it compares to other tools
Frequently asked questions
What decibel level is considered dangerous?
NIOSH's widely cited guidance is that continuous exposure above 85 dB(A) for 8 hours or more carries meaningful risk of long-term hearing damage, with safe exposure time roughly halving for every additional 3 dB. Brief exposure to much louder sounds (120 dB+, like a siren at close range) can cause immediate damage. These are general public-health guidelines, not a substitute for professional occupational or medical assessment.
What does dB(A) mean?
dB(A) is A-weighted decibels — a raw sound-pressure measurement adjusted to approximate how sensitive human hearing is across different frequencies (we're less sensitive to very low and very high frequencies than to the mid-range where speech sits). It's the standard weighting used in occupational noise regulations and most consumer sound meters.
How accurate is a phone's microphone for measuring sound levels?
Good enough for everyday awareness — spotting a genuinely loud environment versus a quiet one — but not equivalent to a calibrated professional sound-level meter. Phone microphones vary by model, aren't calibrated to a reference standard, and can behave differently at very high or very low sound levels. For occupational compliance measurement, a dedicated calibrated meter is still the right tool.
What is LEQ, and why does it matter more than a single peak reading?
LEQ (equivalent continuous sound level) is the average sound energy over a period of time, which is what actually correlates with hearing-damage risk — a brief loud spike matters less than a sustained elevated level. A peak reading alone can be misleading; LEQ over a session gives a much better picture of real exposure.