dB Meter

Decibel measurement site is a free browser-based tool that can measure decibels (dB) in real time. It supports measurement of "current volume", "maximum volume", "minimum volume", and "average volume", as well as downloading measurement data.
How to Use
- Click the "Start Measurement" button.
- Grant browser microphone access permission.
- The device's microphone will automatically collect and measure sound levels in real-time.
- Measured data can be downloaded in CSV format.
What is Decibel (dB)?
Decibel (dB) is a logarithmic unit used to measure sound intensity or power levels. It primarily represents ratios, showing how many times greater (or smaller) a value is compared to a reference level rather than representing absolute values.
Characteristics of Decibels
- Logarithmic scale: Since dB uses a logarithmic scale, small numerical changes correspond to large perceptual differences.
Example: 60dB (normal conversation) → 70dB (vacuum cleaner) → 80dB (traffic noise)
→ A 10dB increase means the sound energy increases approximately 10 times - Main calculation formula:
For sound pressure level:
dB = 20 log10(P / P0)
※ P0 is the reference sound pressure (20μPa) - Matched to human hearing:
The dB scale aligns with human auditory perception (logarithmic sensitivity), making it ideal for acoustic measurements and noise evaluation.
Sound Level Reference (dB)
Sound Level | Example |
---|---|
10 dB | Breathing sound |
30 dB | Library, suburban area at night |
50 dB | Quiet office, air conditioner sound |
60 dB | Normal conversation |
80 dB | Busy traffic road |
100 dB | Under train tracks, construction site |
120 dB | Rock concert, ambulance siren |
140 dB | Near airplane engine (pain threshold) |
Precautions
- Sounds above 120dB can risk hearing damage.
- Repeated exposure to sounds over 100dB, even briefly, can cause hearing loss.
In summary, decibel (dB) is an indicator of sound intensity and serves as an important unit for evaluating perceived loudness and safety standards.
Notes
This tool is available for free.
*This program was created and tested using PHP8.2.22.
*Please send us your opinions and requests (requests for improvements) for all users.