dB Meter

A needle-style dB meter for quick checks: the live A-weighted level, the session Leq and the peak, plus a one-minute graph. For a fair comparison between places, measure for at least a minute and compare Leq values rather than single peaks.

How to use

1. Tap Start and allow the microphone. The big number is the current level in approximate dB(A), updated about ten times a second.
2. Min and Max are the quietest and loudest readings (fast, 125 ms), Avg is the average of the per-second levels and Leq is the energy average for the whole session, the figure standards use.
3. The graph shows the last minute. Every second is logged; download the log as a CSV file with the button next to Start.
4. Turn on Neighbor to compare the last minute with Korea’s apartment floor-noise limits for day or night.
5. For better accuracy, open Calibrate and enter the reading of a real sound level meter placed next to your device. The correction is saved in this browser.

• This is not a certified sound level meter (IEC 61672 class 1 or 2). Phones and laptops use small microphones with their own gain and filters, so readings are approximate. Uncalibrated readings can be off by 10 dB or more; after calibration, phone microphones typically agree with a meter within about ±5 dB at everyday levels, less well at very low and very high levels.
• The A-weighting filter follows the standard curve closely from about 30 Hz to 8 kHz; many phone microphones barely pick up very low or very high frequencies anyway. Very quiet rooms may read high because of the microphone’s own noise.
• Korean apartment floor-noise limits (Rules on the Scope and Standards of Floor Noise in Apartment Buildings): impact noise such as footsteps, 1-minute Leq 39 dB(A) by day (06–22) and 34 dB(A) at night (22–06), maximum level 57 and 52 dB(A); airborne noise such as TV or music, 5-minute Leq 45 and 40 dB(A). Shown for reference only. Official assessments use certified meters and a set procedure, so this result cannot be used as evidence.
• For comparison, the WHO guideline for bedrooms at night is 30 dB(A) Leq and 45 dB(A) for single noise events.
• Hearing: long exposure above about 85 dB(A) can damage hearing. NIOSH recommends no more than 8 hours at 85 dB(A), halving the time for every 3 dB more.
• Audio is analysed on your device and never recorded or sent anywhere. The screen stays on while measuring if your browser allows it.

How loud is loud?

Decibels are logarithmic: every 10 dB more is ten times the sound energy and sounds roughly twice as loud, and +3 dB doubles the energy. Typical A-weighted levels: a quiet bedroom at night 25–30 dB, a library 35–40, normal conversation at 1 m about 60, a busy street 70–80, a loud bar or concert 95–110.

For hearing, NIOSH recommends no more than 8 hours a day at 85 dB(A), halving the time for every 3 dB more: 4 hours at 88, 1 hour at 94 and only 15 minutes at 100. For sleep, the WHO guideline for bedrooms is 30 dB(A) Leq at night.

What the readings mean

The big number is the current level, updated about ten times a second. Min and Max use fast (125 ms) readings. Avg is the plain average of the per-second levels, while Leq is the energy average over the whole session, the figure used in noise standards; because loud moments carry more energy, Leq is usually higher than Avg. A dB(A) value applies the A-weighting curve, which de-emphasises low and very high frequencies the way human hearing does.

Accuracy and calibration

Phones and laptops are not certified sound level meters (IEC 61672 class 1 or 2). Their microphones apply their own gain and filtering, so an uncalibrated reading can be off by 10 dB or more. Place a real meter next to your device, enter its reading in Calibrate, and the correction is saved; phones then typically agree within about ±5 dB at everyday levels.

Frequently asked questions