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Online Classroom Noise Meter
Visualize surrounding volume using your device microphone.
Online Classroom Noise Meter result
The browser requests microphone permission and analyzes time-domain RMS on this device; audio is never recorded or uploaded. This is a relative signal display, not calibrated dB or sound-pressure level. Microphone hardware, placement, automatic gain processing, browser support, operating system, and room acoustics can change readings. Set the alert threshold by observing your own room; do not use this meter for hearing-safety decisions.
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How this tool works
The meter requests microphone permission, samples 1,024 time-domain microphone values through the Web Audio API, calculates their root-mean-square amplitude, applies the visible sensitivity multiplier, and compares the resulting device-relative 0–100 signal with the user-selected alert threshold. It does not calculate calibrated decibels.
Assumptions
The 0–100 display is a device-relative RMS amplitude after the visible sensitivity multiplier. The alert threshold is chosen by the visitor for the current room and is not a calibrated decibel limit.
Limits to know
The reading is relative to the current microphone and automatic gain settings, not a calibrated sound-pressure-level or decibel measurement. Browser permission, microphone placement, device hardware, room acoustics, and operating-system processing can change the displayed level.