# Sound Decibel Meter

> Free, browser-based A/C/Z-weighted sound level meter. All audio processing happens locally — nothing is uploaded. Works on iOS Safari, Android Chrome, and desktop Chromium / Firefox / Safari. Once calibrated, agreement is typically within ±2 dB of a Class 2 reference for steady mid-range sources.

Sound Decibel Meter helps people measure the noise in their lives accurately, understand what the numbers mean, and act on them. The site is supported by occasional affiliate links to third-party hearing protection on contextually relevant pages, disclosed inline. There is no premium tier, no display ads, no audio analytics product, and no audio ever leaves the user's device.

## The meter
- [Live decibel meter](https://sounddecibelmeter.org/): Real-time A-, C-, or Z-weighted SPL with FFT visualizer, statistics (Min / Avg / Max / Peak), and a reference chart from 0 dB to 140 dB.

## Documentation
- [guide](https://sounddecibelmeter.org/guide): Step-by-step user guide for the in-browser meter.
- [comparison](https://sounddecibelmeter.org/comparison): Reference chart of everyday sound levels in 10-decibel bands.
- [calibration](https://sounddecibelmeter.org/calibration): Three calibration methods for phone and laptop mics.
- [tips](https://sounddecibelmeter.org/tips): Field-tested techniques for accurate, repeatable readings.
- [health](https://sounddecibelmeter.org/health): Noise-induced hearing loss biology, thresholds, and protection.
- [workplace](https://sounddecibelmeter.org/workplace): OSHA, NIOSH, and EU 2003/10/EC noise standards explained.
- [use-cases](https://sounddecibelmeter.org/use-cases): Real-world scenarios with target levels and interventions.
- [science](https://sounddecibelmeter.org/science): Physics of sound, decibel math, weightings, FFT, and Leq.
- [glossary](https://sounddecibelmeter.org/glossary): Plain-language definitions of acoustics and hearing terms.
- [faq](https://sounddecibelmeter.org/faq): Honest answers to the most common questions about the meter.
- [about](https://sounddecibelmeter.org/about): Project mission, methodology, privacy stance, and roadmap.

## Legal
- [privacy-policy](https://sounddecibelmeter.org/privacy-policy): What we collect (almost nothing) and why.
- [terms-of-service](https://sounddecibelmeter.org/terms-of-service): Use, accuracy disclaimers, and liability terms.
- [contact](https://sounddecibelmeter.org/contact): Email and what to write to us about.

## Optional
- [llms-full.txt](https://sounddecibelmeter.org/llms-full.txt): Full Markdown source of every documentation page, concatenated for ingestion.