How to use this decibel meter
Press Start and allow microphone access. The large number is the current A-weighted level, updated every 0.1 seconds. Below it you get the 1-minute equivalent level (Leq), the maximum level and the overall average for the session.
- Place your phone on a table or shelf about 1.2–1.5 m (4–5 ft) above the floor, away from walls. Holding it adds handling noise.
- Turn off sources you do not want to measure, such as a TV, fan or air purifier.
- Measure for at least a minute. Leq needs 60 seconds of data before it appears.
- For long sessions keep the charger connected. Supported browsers keep the screen awake while measuring.
- Use Export CSV or Save chart image to keep a record.
What dB(A), Leq and Lmax mean
dB(A) is sound level weighted toward the frequencies human ears hear best. Most noise regulations use it, and this meter applies a standard A-weighting filter.
Leq (equivalent continuous level) averages sound energy over a period. A single bang in an otherwise quiet minute raises Leq only a little. Lmax is the loudest moment.
Typical noise levels
Approximate values; real levels depend heavily on distance and the room.
- 20–30 dB: whisper, very quiet bedroom
- 30–40 dB: quiet library, residential street at night
- 40–50 dB: quiet office, refrigerator hum
- 50–60 dB: normal conversation
- 60–70 dB: vacuum cleaner, busy restaurant
- 70–80 dB: heavy traffic
- 85 dB and above: risk of hearing damage with long exposure. NIOSH recommends limiting exposure at 85 dB(A) to 8 hours, halved for every 3 dB increase.
Accuracy and calibration
Phone and laptop microphones differ in sensitivity, and some devices apply automatic gain. This meter asks the browser to turn off auto gain, echo cancellation and noise suppression, but some devices may still process the signal. Readings are best for comparing levels over time on the same device.
If you have a calibrated sound level meter, measure simultaneously and enter its reading under Calibration. The offset is stored in your browser for next time. Phone readings are not a substitute for certified measurements in legal or workplace settings.
FAQ
Is my audio recorded or uploaded?
No. The meter only computes loudness inside your browser. Nothing is stored or sent anywhere.
Why are my readings too high or too low?
Microphone sensitivity varies by device. Use Calibration with a reference meter, or check a quiet room (about 30–35 dB) and adjust the offset.
Does it work on iPhone and Android?
Yes, in recent versions of Safari, Chrome and Samsung Internet. Allow microphone access when asked.
Why does 1-min Leq say it is still measuring?
Leq needs 60 seconds of data. After the first minute it updates continuously with the most recent minute.
Will it keep measuring with the screen off?
Many mobile browsers pause the microphone when the screen turns off or you switch apps. The meter requests a screen wake lock while running, but keep the screen on and the charger connected for long sessions.