How to Use the Online Decibel Meter

1. Allow the microphone

Press Start and accept the browser prompt. Use HTTPS; file:// and plain HTTP origins may block capture. Pick the input in the selector if you have several. If nothing happens, follow microphone troubleshooting.

2. Place the device and read the panel

Set the device on a stable surface at ear height, away from wind, vents and handling. The gauge immediately shows an estimated dBA value using a nominal device offset. Current is the smoothed live value; Leq is the energy average; min/max bracket the session. Wait a few seconds for Fast/Slow smoothing to settle, then calibrate your microphone for better device-specific accuracy.

3. Tune, compare and export

Choose A-weighting for everyday checks (see dB vs dBA), compare against the decibel comparison chart, then export CSV for spreadsheets or JSON for code. History stays in this browser only (privacy).

Run a clean 30-to-60-second session

1. Set the device on a stable surface at ear height with the microphone uncovered, a metre from vents and keyboards.
2. Press Start, grant the once-per-origin permission over HTTPS, and let Fast or Slow smoothing settle for five seconds.
3. Stay still and silent while current, minimum, Leq, maximum and duration accumulate. The 240-point graph shows whether a passing truck or a tapped table spoiled the sample.
4. Stop a second pass the same way before comparing. Two matched 45-second Leq values beat ten glanced live numbers.

Capture stays mono with echo cancellation, noise suppression and automatic gain requested off where the browser allows it, and input never plays through speakers. The headline figure is an estimate from weighted dBFS plus a nominal offset until you add a device-specific calibration against a known reference in the same spot.

Save, revisit and export without an account

Up to 20 recent sessions stay in this browser only, so a bedroom-to-office comparison survives a reload but never uploads anywhere. Exports carry dB values only from calibrated sessions; uncalibrated history exports without dB figures to avoid dressing a rough estimate as a record. Pull CSV into a spreadsheet for a noise diary or JSON into code for charts, then consult privacy for storage details. No accounts, no downloads, no install — a current Chrome, Edge, Firefox or Safari is enough.

If the reading looks stuck or too quiet

• Idle dashes. Dashes mean no samples yet, never a simulated zero. Reselect the intended input, close calls or recorder tabs, and press Start again.
• Suspiciously low line. Check for a covered microphone, a wrong input choice, or a case muffling the port. Retest uncovered on a table.
• Wild jumps. Handling, wind and tapping dominate small capsules. Set the device down, step back, and average a full minute instead of trusting peaks.

When faults persist, work through microphone troubleshooting, then read accuracy and limitations and how the meter works before drawing conclusions.

Open the online decibel meter → · How the meter works →