About this tool
This sound level meter measures how loud your surroundings are, right in the browser – using the microphone of your smartphone, tablet or laptop. It shows the current level in dB(A) or unweighted in dB(Z), plus minimum, maximum, the energy average Leq and a chart of the last 30 seconds. A table of typical sounds helps you put the numbers into context.
A-weighting models that the ear perceives low and very high tones as quieter; it is computed from the frequency spectrum according to IEC 61672. The time weighting “Fast” (125 ms) follows short sounds, “Slow” (1 s) calms the display. The microphone signal is analysed only locally and never recorded. Which frequencies a sound contains is shown by the Spectrum Analyzer; convert levels with the dB Calculator.
How it works
- Tap “Start measuring” and allow microphone access.
- Hold the device with its microphone (usually at the bottom of a phone) uncovered and pointed towards the sound source.
- Read the level, average and maximum. For more accurate values, match the calibration offset once against a real sound level meter.
Frequently asked questions
How accurate is a sound level meter in the browser?
Phone microphones are not calibrated and differ from model to model. Without calibration, deviations of 5 to 10 dB are common; very quiet (below about 30 dB) and very loud sounds (above about 100 dB) are often beyond what the microphone can capture. For comparisons on the same device, such as before/after, the values work well anyway.
What is the difference between dB(A) and dB(Z)?
dB(Z) is the unweighted sound pressure level across all frequencies. dB(A) weights frequencies the way the human ear perceives them at moderate volume: low tones count much less. Noise limits and guidelines are almost always given in dB(A).
What does Leq mean?
Leq is the equivalent continuous sound level: the constant level that would carry the same sound energy over the same time. Because decibels are logarithmic, short loud moments raise the Leq more than a simple average would.
How do I calibrate the measurement?
Place a real sound level meter next to your phone, play a steady sound (e.g. noise from a speaker) and change the calibration offset until both displays match. The offset is stored only in your browser and applies to this device.
Is the sound recorded or uploaded?
No. The tool reads the microphone in short blocks, computes the level and discards the data immediately. Echo cancellation, noise suppression and automatic gain are switched off so they don’t distort the measurement.