FAQ · Measurement limits
Is an iPhone decibel meter accurate?
An iPhone decibel meter can be useful for quick awareness checks. It should not be treated as a certified sound level meter. That distinction is the whole point of Honest Decibel.
The short answer
Useful: checking whether a room is quiet, loud, or obviously extreme; comparing spots in the same environment; logging personal context. Not enough: legal proof, workplace compliance, medical decisions, formal acoustics, or calibrated testing.
What affects accuracy
- Phone model and microphone response.
- Phone case or blocked microphone.
- Distance from the source.
- Wind and handling noise.
- Room reflections and directionality.
- A-weighting, time averaging, and whether the sound is steady or spiky.
How to get a more useful reading
Measure from the position of your ears. Keep the phone still. Avoid covering the microphone. Measure for 20 to 60 seconds. Write down context: source, distance, room, and whether the level was steady.
When to stop using a phone meter
If the result will be used in a legal complaint, workplace compliance process, school/venue policy, hearing-health decision, or equipment specification, use a certified meter and a qualified professional.