Sound Level Meter

Sound Level Meter is a professional-grade online sound measurement tool that uses your device's microphone to provide real-time decibel readings, frequency analysis, and comprehensive acoustic metrics directly in your browser.

What is Sound Level Meter?

Sound Level Meter is a free web-based application that measures ambient sound levels in real time using your device's built-in microphone. It outputs A-weighted, C-weighted, or Z-weighted decibel readings along with MIN, AVG, MAX, and PEAK metrics, a frequency spectrum visualization, and sound classification labels. The tool runs entirely in the browser with no installation or registration required, and is developed and maintained by the team at soundlevelmeter.org.

Key Features

• Real-time decibel monitoring — Instant readings with adjustable update intervals: Realtime (50 ms), Fast (250 ms), Slow (1 s), or Very Slow (2 s).
• Frequency analysis — FFT-based spectrum display shows real-time frequency distribution, helping identify dominant tones and acoustic characteristics.
• Multiple metrics tracking — Tracks MIN, AVG, MAX, and PEAK sound levels throughout a session, displayed with duration counter.
• Professional weighting filters — Choose between dBA (human ear response), dBC (flat response), and dBZ (zero weighting) for accurate measurement standards.
• Calibration offset control — Adjust measurements with a configurable dB offset and sensitivity slider (0–100%).
• Interactive visual charts — Includes a sound level history graph, bar meter, and frequency display for comprehensive data visualization.
• Sound classification — Real-time labeling of sound levels with common noise source references (e.g., quiet room, conversation, traffic).
• No sign-up required — Start measuring immediately after granting microphone permission.

Who is it for?

• Acoustic engineers and environmental specialists — Conduct noise surveys and monitor ambient sound levels for compliance or research.
• Audio professionals and sound technicians — Analyze frequency content and balance sound systems in venues or studios.
• Occupational health and safety professionals — Assess workplace noise exposure to ensure compliance with safety regulations.
• Music producers and audio enthusiasts — Check recording environment noise floor or calibrate monitoring levels.

What can you do with it?

• Noise monitoring: Measure and log sound levels in offices, factories, schools, or public spaces to identify noise pollution sources.
• Frequency analysis: Visualize the frequency spectrum to pinpoint problematic resonances or validate acoustic treatments.
• Calibration testing: Use weighting filters and offset adjustments to align readings with professional sound level meters.
• Educational demonstrations: Show sound wave properties and decibel scales in classroom or lab settings.

How does it work?

Visit the website, click "Start Measuring", and grant microphone access. Select a weighting filter and update interval, then observe the real-time decibel reading, metric panels, and frequency spectrum. The tool automatically begins logging MIN, AVG, MAX, and PEAK values until you stop the session.

Pros and cons

• Pro: Completely free and works on any device with a browser and microphone.
• Pro: Offers professional-grade features like FFT analysis and multiple weighting curves.
• Con: Measurement accuracy depends on the quality of the device's built-in microphone and may not match calibrated hardware meters.
• Con: No built-in export or save feature for measurement logs (data disappears on page refresh).

Pricing

Sound Level Meter is free to use with no registration, subscription, or hidden fees.

FAQ

How does the Sound Level Meter work?

It accesses your device's microphone to capture audio, processes it using real-time FFT and RMS calculations, and displays the sound level in decibels with user-selectable weighting and update intervals.

What sound metrics does it measure?

It measures current, minimum, average, maximum, and peak sound levels in decibels (dBA, dBC, or dBZ), along with duration of the session and a real-time frequency spectrum.

Can I use it for professional sound measurement?

Yes, it includes professional calibration options (weighting filters and offset) and is suitable for preliminary surveys, educational use, and non-critical applications. For certified measurements, a calibrated external microphone and meter are recommended.

What devices and browsers are supported?

Any device with a modern web browser (Chrome, Firefox, Safari, Edge) and a microphone. It works on desktops, laptops, tablets, and smartphones.

Is it free?

Yes, Sound Level Meter is entirely free with no advertisements or usage limits.