About this tool

SoundMeter is a browser-based sound level meter. It uses your device's microphone and the Web Audio API to show approximate decibel readings, frequency spectra, and waveforms.

It's useful for getting a rough sense of noise levels - comparing rooms, checking if a space is quiet enough for recording or calls, displaying noise feedback in a classroom, or just satisfying curiosity about how loud something is.

What it's not

It's not a calibrated instrument. The readings are approximate. Consumer microphones have frequency response limitations, browsers may not fully disable audio processing, and there's no traceable calibration. Don't use this for OSHA compliance, legal documentation, medical assessment, or any situation where measurement accuracy has real consequences.

How it's built

• Framework: Astro (static site generation)
• Styling: Tailwind CSS v4
• Audio: Web Audio API AnalyserNode, 2048-point FFT
• Language: TypeScript
• Hosting: Static CDN
• Backend: None. Static files only.

Privacy

No audio leaves your device. No accounts, no tracking within the measurement interface. The site loads fonts from Google Fonts (their privacy policy applies to that request). That's it.

Contact

Bugs or questions: hello@onlinesoundmeter.com