Skip to main content
LibraTool logoLibraTool

Free Decibel Meter

Measure sound level from your microphone in real time, with min/max/average and a 60-second scrolling history — right in your browser.

Works offline once loaded

Current level

—dB (approx.)

Raw microphone level: — dBFS

dB

Shifts the raw microphone reading toward an approximate dB SPL value. Tune it against a known reference (e.g. a calibrated SPL meter or app) if you have one.

This is an approximation, not a calibrated measurement. Phone and laptop microphones vary wildly in sensitivity, so without dedicated SPL-meter hardware, these readings can only ever be a rough estimate — useful for comparing levels, not for safety-critical decisions.

Min

—

Max

—

Average (Leq)

0.0

Last 60 seconds

Common sound levels for reference

  • Whisper~30 dB
  • Quiet room~40 dB
  • Normal conversation~60 dB
  • Busy traffic~80 dB
  • Motorcycle~95 dB
  • Rock concert~110 dB
  • Threshold of pain~125 dB

Your files never leave your device. All processing happens locally in your browser.

How It Works

Turn your microphone into a rough sound-level meter, entirely in your browser.

  1. 1
    Allow microphone access
    Tap Start metering and grant the browser permission to use your microphone.
  2. 2
    Watch the live reading
    The current level, plus running min, max and average (Leq), update several times a second.
  3. 3
    Adjust the calibration offset
    Tune the offset against a known reference to nudge the raw reading toward an approximate SPL value.
  4. 4
    Review the 60-second history
    The scrolling chart shows how the level has changed over the last minute; hit Reset to clear it.

Microphone audio is analyzed locally in your browser only — it is never uploaded, recorded, or saved anywhere.

Related Tools

🎙️

Microphone Test

Check that your microphone works before a call or recording: pick the input device, watch a live level meter and waveform, and record a 5-second playback sample.

Try it
🎨

Drawing Pad

Sketch, write and draw shapes on a canvas with a pressure-aware pen, marker, highlighter, eraser and text, undo mistakes, then save a PNG or a transparent PNG.

Try it
📏

Bubble Level

Check if a surface is level with your phone: a round bubble level when flat, a bar level on its edge, tilt in degrees and a beep when level.

Try it

Frequently Asked Questions