Online Decibel Meter - Free Sound Level Measurement
Check estimated sound levels instantly with our free online decibel meter. It works directly in your browser using your device's microphone; calibration is optional.
The instant result uses a generic microphone mapping. Calibration is optional and can improve the estimate for this device; results are not dBA or certified measurements.
Measurement History
0 records saved
No measurement records yet
Start a measurement to save data
Click "Start Measurement" to begin checking an estimated sound level immediately.
You'll need to allow microphone access when your browser asks.
How to Use
Step-by-step guide to instant sound estimates and optional calibration
Decibel Chart
See how loud common sounds are in decibels
Hearing Protection
Compare NIOSH and OSHA references and learn how hearing protection is selected
What You Can Do
Instant browser-based sound estimates with optional calibration
Live Readings
See an estimated sound level update immediately with a live waveform
Track Your Data
View max, min, and average readings from your measurement sessions
Optional Device Calibration
Optionally compare with a real sound level meter to refine this device's estimate
Save Results
Download your measurement data as CSV or JSON files
What is a Decibel Meter?
A sound level meter measures calibrated acoustic sound pressure. This browser tool provides an immediate estimated dB SPL value from the microphone and supports optional device-specific calibration.
The Science Behind Decibel Measurement
Understanding how sound is measured helps you interpret the readings better.
Sound Pressure Level (SPL)
A certified sound level meter measures air-pressure changes with a calibrated microphone. This browser tool instead converts digital microphone input through a generic baseline to provide an immediate estimate; optional comparison with a real meter can refine that estimate.
The Logarithmic Scale
The decibel (dB) is a logarithmic unit. This means every 10 dB increase represents a ten-fold increase in sound intensity. For example, 80 dB is 10 times more intense than 70 dB, and 100 times more intense than 60 dB. A small increase in decibels means a huge increase in noise energy.
A-Weighting (dBA)
A-weighting is a standardized frequency filter used by suitable sound level meters. This browser tool does not implement a certified A-weighting filter, so its output must not be described as dBA or used to compare with regulatory limits.
How to Use
Allow Access
Grant microphone permission when your browser asks
Start Measuring
Click Start to see an estimated sound level immediately
View Results
Watch the live readings and waveform display
Export Data
Save your measurements if you need them later
Why Use This Tool?
Free & No Install
Works right in your browser - no apps to download
Your Privacy Matters
All processing happens on your device. We don't record or store any audio.
Transparent Measurement Scale
Readings are labeled as an instant estimate or an optionally calibrated device estimate
Works Everywhere
Use on your phone, tablet, or computer with any modern browser
Common Questions
How accurate is this online decibel meter?
Do I need to download anything?
Is my audio being recorded?
What browsers work with this?
Can this tool determine whether a noise level is safe?
Important Note
This tool is for general reference and educational purposes. Results depend on your device's microphone quality and may not be as accurate as professional sound level meters. For critical applications (workplace safety, legal documentation, medical purposes), please use certified equipment.