Decibel meter
How loud is it? Measure the noise in dB(A) with your microphone.
Now
–dB(A)
- Min
- –
- Max
- –
- Average (Leq)
- –
Browser microphones aren’t calibrated: the reading is an estimate.
Last minute
How loud is that?
- 120Rock concert
- 100Motorbike
- 85Heavy traffic — hearing damage possible with long exposure
- 70Vacuum cleaner
- 60Normal conversation
- 40Quiet library
- 30Whisper
- 0Threshold of hearing
Nothing leaves your device
This tool runs entirely in your browser. What you type, play or record here stays on your device: nothing is uploaded or saved on a server.
Example
Example: 10 minutes in a bedroom at night, and why the average is 51 dB, not 42
Music from next door keeps you awake. You put the phone on the bedside table, choose Response “Slow (1 s)”, press Start and leave it 10 minutes. For 8 minutes the room reads about 38 dB(A); for 2 minutes the bass comes through at about 58.
- Min 38.0 and Max 58.0 are the quietest and loudest the slow reading got; the graph shows only the last minute.
- Average (Leq) adds up sound energy, not decibels: 2 minutes at 58 carry far more energy than 8 at 38, so Leq is 51.2 dB(A), not the 42 you get by averaging the numbers.
- The badge under the reading stays on “OK” all along; it turns red and says “Loud” only from 85 dB(A).
- Keep the page open and the screen on for the whole measurement, and press Reset before the next one.
| Minutes at 58 dB(A) | Minutes at 38 dB(A) | Average (Leq) over 10 minutes |
|---|---|---|
| 0 | 10 | 38.0 dB(A) |
| 1 | 9 | 48.4 dB(A) |
| 2 | 8 | 51.2 dB(A) |
| 5 | 5 | 55.0 dB(A) |
Two loud minutes lift the 10-minute average by 13 dB. Browser microphones are not calibrated, so the figures are an estimate; matching the reading to a real meter with Calibrate brings them closer.
How it works
- Press Start and allow the microphone; keep the phone or laptop where you want to measure, not covered.
- Read the level now, the minimum and maximum, and the average (Leq) over the whole measurement; the graph shows the last minute.
- For the best accuracy, press Calibrate and adjust the reading to match a real sound level meter.
Frequently asked questions
- How accurate is an online decibel meter?
- It is an estimate. Browser microphones are not calibrated and every device has its own sensitivity, so readings can be several decibels off — good for comparing and spotting loud noise, not for legal or workplace measurements. Calibrating against a real meter makes it much closer.
- What does dB(A) mean?
- Decibels A-weighted: the level adjusted the way the ear hears, less sensitive to very low and very high pitches. It is the unit noise limits and sound level meters use.
- How loud is too loud?
- Around 85 dB(A) — heavy traffic — hearing can be damaged by long exposure; every 3 dB more halves the safe time. A normal conversation is about 60 dB(A), a quiet room 30–40.
- What is the average (Leq)?
- The equivalent continuous level: the steady level with the same sound energy as everything measured. Loud moments count more than quiet ones, as they do for hearing.
- Fast or Slow: which response should I use?
- Fast (125 ms) follows sudden sounds; Slow (1 s) gives a steadier number for traffic or a room. A door slam of a fifth of a second at 80 dB(A) in a 38 dB room peaks at about 79 on Fast but only about 73 on Slow. The average (Leq) is the same either way.
- How does calibration work?
- Press Calibrate and move the reading up or down in 1 dB steps, up to 20 dB either way, until it matches a real sound level meter in the same spot. The browser remembers the setting, and it shifts the reading, the minimum, maximum, average and graph together.
- Is the sound recorded?
- No. It runs in your browser; nothing is recorded or sent anywhere.