Decibel Meter
Measure ambient sound with your microphone. Start for a live readout — estimated dB SPL against everyday sounds, or exact dBFS for audio work. Peak, average, and minimum build up as it runs.
The meter needs microphone access to measure sound levels. Everything is analyzed on your device — no audio is recorded or uploaded.
The sound level is computed locally in your browser — nothing is recorded or sent anywhere.
- 120 dBPain threshold
- 100 dBRock concert
- 80 dBHeavy traffic
- 60 dBNormal conversation
- 40 dBQuiet room
- 20 dBWhisper
SPL is estimated from an uncalibrated mic. Same-device comparisons are meaningful; the absolute number is a ballpark.
Level falls off quickly with distance. Comparing two sounds? Keep the mic in the same spot, at the same distance.
Sustained exposure above ~85 dB SPL damages hearing over a workday — every 3 dB more halves the safe time.
A decibel meter — a sound level meter — tells you how loud your surroundings actually are. Your ears adapt within minutes, so a noisy office or a droning fan fades into "normal." This one runs in your browser: check room noise before recording, compare two keyboards, measure how much street noise reaches your desk, or watch the level when the AC kicks in. Audio is analyzed on your device and never leaves it.
Press start and the browser opens your mic through the WebRTC API, with automatic gain, noise suppression, and echo cancellation off — each would rewrite the level a meter should report. The Web Audio API measures signal strength (RMS) many times per second and converts it to decibels. The native reading is dBFS — always zero or negative relative to the loudest your mic can report — and dB SPL is estimated from it with a fixed offset.
How accurate is a browser decibel meter?
Treat the SPL figure as an estimate, not a measurement. A real SPL meter has a calibrated mic; yours has unknown sensitivity, so the same room can read 10 dB apart on two devices. What a browser meter is good at is relative comparisons on the same device: quieter than an hour ago, which keyboard is louder, how many dB the new fan added. dBFS has no such caveat — it is exact for what your mic delivers, which is why audio software uses it. For legal measurements (workplace noise, neighbor disputes), you need a calibrated class 1 or class 2 meter.
Common sound levels
| dB SPL | Sound | Exposure |
|---|---|---|
| 20 dB | Whisper, rustling leaves | Harmless |
| 40 dB | Quiet room, library | Harmless |
| 60 dB | Normal conversation | Harmless |
| 70 dB | Vacuum cleaner, busy office | Annoying, but safe |
| 85 dB | Heavy traffic, blender | Hearing damage after ~8 hours a day |
| 100 dB | Nightclub, motorcycle | Damage after ~15 minutes |
| 120 dB | Siren at close range, rock concert front row | Pain threshold — immediate risk |
| 140 dB | Fireworks, jet engine nearby | Instant permanent damage possible |