How accurate is a decibel meter on a phone or laptop?

Close, but not exact. Phone and laptop microphones are not calibrated and differ from one another by several decibels, so treat a reading as an estimate. If you have a sound level meter you trust, measure the same steady sound with both and set the calibration to the difference — it is remembered on this device.

What does dB(A), or A-weighting, mean?

Hearing is far less sensitive to deep and very high pitches than to the middle, so sound level meters weigh frequencies the way the ear does. This one uses A-weighting, the standard for noise: a 100 Hz hum counts about 19 dB quieter than a 1 kHz tone of the same pressure.

How loud is too loud?

NIOSH recommends no more than 85 dB(A) averaged over an eight-hour day, and every 3 dB above that halves the safe time: 88 dB for four hours, 94 dB for one, 100 dB for fifteen minutes. Compare the average against those, not the loudest moment — one door slam is not an exposure.

What does the frequency spectrum show?

The reading split by pitch into ten octave bands, from deep bass at 31.5 Hz to treble at 16 kHz — the same split as a ten-band graphic equaliser. The bars are A-weighted like the reading, so their energy adds up to it: two bars at 50 dB make 53, not 100.

Why is the average so close to the loudest reading?

Because it averages sound energy, as sound level meters do, rather than the numbers on screen. Decibels are logarithmic, so loud moments dominate: ten seconds at 90 dB and fifty seconds at 50 dB average to 82 dB, not 57.

Is the sound recorded or uploaded?

No. The microphone opens only when you press Start, and the sound is measured as it arrives, inside this tab — nothing is recorded, stored or sent anywhere. The microphone is released as soon as you press Stop or leave the page.

Decibel Meter: Measure Sound Level in dB Online

Readings are estimates: phone and laptop microphones are not calibrated. The sound is measured in this tab and never recorded or sent anywhere.

Sound level:—dB

Press Start and allow the microphone to see the level.

— Quietest
— Average
— Loudest

Frequency spectrum

Calibration: 0 dB

Microphones differ. If a sound level meter you trust reads 3 dB higher than this one for the same steady sound, set +3. Saved on this device only.

How loud is that?

Typical levels of everyday sounds, rounded. The real figure depends on the source and how far away you are from it.

Sound	Typical level
A ticking watch	20 dB
A soft whisper	30 dB
A refrigerator humming	40 dB
Normal conversation	60 dB
A washing machine or dishwasher	70 dB
City traffic, heard from inside a car	85 dB
A motorcycle	95 dB
A car horn 5 metres away	100 dB
A rock concert	110 dB
A siren, standing close by	120 dB
Fireworks, close by	140 dB

Common questions

How accurate is a decibel meter on a phone or laptop?
Close, but not exact. Phone and laptop microphones are not calibrated and differ from one another by several decibels, so treat a reading as an estimate. If you have a sound level meter you trust, measure the same steady sound with both and set the calibration to the difference — it is remembered on this device.
What does dB(A), or A-weighting, mean?
Hearing is far less sensitive to deep and very high pitches than to the middle, so sound level meters weigh frequencies the way the ear does. This one uses A-weighting, the standard for noise: a 100 Hz hum counts about 19 dB quieter than a 1 kHz tone of the same pressure.
How loud is too loud?
NIOSH recommends no more than 85 dB(A) averaged over an eight-hour day, and every 3 dB above that halves the safe time: 88 dB for four hours, 94 dB for one, 100 dB for fifteen minutes. Compare the average against those, not the loudest moment — one door slam is not an exposure.
What does the frequency spectrum show?
The reading split by pitch into ten octave bands, from deep bass at 31.5 Hz to treble at 16 kHz — the same split as a ten-band graphic equaliser. The bars are A-weighted like the reading, so their energy adds up to it: two bars at 50 dB make 53, not 100.
Why is the average so close to the loudest reading?
Because it averages sound energy, as sound level meters do, rather than the numbers on screen. Decibels are logarithmic, so loud moments dominate: ten seconds at 90 dB and fifty seconds at 50 dB average to 82 dB, not 57.
Is the sound recorded or uploaded?
No. The microphone opens only when you press Start, and the sound is measured as it arrives, inside this tab — nothing is recorded, stored or sent anywhere. The microphone is released as soon as you press Stop or leave the page.

Tools

Decibel meter