Free Online Decibel Meter — Measure Sound Level Instantly

How It Works

Click Start & Allow Microphone Access

Hit the "Start Measuring" button and grant microphone permission when prompted. Works in Chrome, Firefox, and Safari on desktop and mobile.

Watch Your Real-Time dB Level

The meter responds instantly to sound in your environment. Green indicates quiet levels, yellow is moderate, and red warns you of loud or clipping signals.

Compare Against Reference Levels

Use the sound level reference table to understand what your readings mean — from whisper-quiet to concert-loud — and check if your levels are safe.

Understanding Decibels and Sound Levels

What Is a Decibel?

A decibel (dB) is a logarithmic unit that measures sound intensity. Because human hearing perceives loudness on a logarithmic scale, decibels provide an intuitive way to express sound levels. Doubling the acoustic energy increases the perceived level by about 3 dB. In everyday terms, 0 dB SPL is the threshold of human hearing, a whisper is about 30 dB, normal conversation sits around 60 dB, and a rock concert can exceed 110 dB.

dBFS vs dB SPL — What This Meter Measures

This browser-based meter displays dBFS (decibels relative to full scale), not dB SPL. In digital audio, 0 dBFS is the absolute maximum — the loudest signal before clipping. All usable levels are negative: -20 dBFS is moderate, -6 dBFS is loud. Consumer microphones are not calibrated for absolute sound pressure, so readings are best used for relative comparisons and monitoring digital recording levels rather than measuring exact room loudness.

Safe Listening Levels

Prolonged exposure to sounds above 85 dB SPL can cause hearing damage. At 85 dB (heavy city traffic), safe exposure maxes out at about 8 hours. Every additional 3 dB halves the safe duration — 88 dB allows 4 hours, 91 dB just 2 hours. Sounds above 100 dB (power tools, concerts without ear protection) can cause damage within minutes. Musicians, producers, and anyone working in loud environments should monitor levels regularly.

Why Monitoring Matters for Music Production

Decibel meters are essential throughout recording, mixing, and mastering. During recording, engineers target peaks around -12 to -6 dBFS for clean signal-to-noise ratio without clipping. In mixing, level meters help balance tracks and preserve dynamic range. For mastering, streaming platforms like Spotify target -14 LUFS integrated loudness. Monitoring your levels ensures your music translates well across all playback systems — from studio monitors to phone speakers.

Frequently Asked Questions

What is a decibel (dB) and how is it measured?

A decibel (dB) is a logarithmic unit used to measure sound intensity. Because human hearing perceives loudness logarithmically, decibels map more naturally to our experience than linear units — doubling acoustic energy only increases perceived loudness by about 3 dB. Sound pressure level (SPL) is measured with calibrated microphones and expressed in dB SPL, where 0 dB SPL is the quietest sound humans can detect (about 20 micropascals). In digital audio, levels are instead measured in dBFS (decibels relative to full scale), where 0 dBFS is the maximum signal level before distortion occurs.

What decibel level is considered too loud or dangerous?

Prolonged exposure to sounds above 85 dB SPL — roughly the level of heavy city traffic — can cause hearing damage over time. Safe exposure at 85 dB is limited to about 8 hours. For every 3 dB increase, the safe duration is cut in half: 88 dB allows 4 hours, 91 dB just 2 hours. Sounds above 100 dB SPL (power tools, loud concerts, headphones at maximum volume) can cause damage within minutes. Anything above 120 dB SPL, such as jet engines or gunshots, causes immediate pain and can result in permanent hearing loss.

What is the difference between dB SPL and dBFS?

dB SPL (Sound Pressure Level) measures absolute acoustic pressure in the physical world using calibrated equipment, where 0 dB SPL is the quietest sound humans can hear. dBFS (decibels relative to Full Scale) measures digital audio levels, where 0 dBFS is the maximum signal before clipping — all usable levels are negative. This browser-based meter shows dBFS because it reads digital audio from your microphone input. It cannot display true SPL readings because consumer microphones are not calibrated for absolute sound pressure. The readings are useful for relative comparisons and monitoring recording levels, but will not match a professional SPL meter.

How do musicians and producers use decibel meters?

Musicians and producers rely on dB meters throughout recording, mixing, and mastering. During recording, they monitor input levels to maintain good signal-to-noise ratio while avoiding clipping — most engineers target peaks between -12 and -6 dBFS. In mixing, level meters help balance individual tracks and set headroom on the master bus to preserve dynamic range. During mastering, loudness targets matter: Spotify recommends -14 LUFS integrated loudness. Live sound engineers also use SPL meters to ensure venue compliance, protect hearing, and keep stage volume in check.

Can I measure sound levels accurately with my phone or computer microphone?

Consumer microphones (laptops, phones, webcams) can measure relative levels but cannot provide accurate absolute SPL readings. They lack calibration against known reference pressures, so the same sound may read differently on different devices. Many devices also apply automatic gain control (AGC), which adjusts sensitivity on the fly and defeats accurate measurement. Browser-based meters like this one are still useful for checking if your mic is working, comparing relative loudness between sources, monitoring digital recording levels, and gauging your environment's noise floor. For precise SPL measurement, use a calibrated sound level meter.

Is this decibel meter free to use? Do I need to install anything?

Yes, this decibel meter is completely free and runs entirely in your browser. There is nothing to download or install — it uses the Web Audio API built into modern browsers (Chrome, Firefox, Safari, Edge). Simply click "Start Measuring," grant microphone permission when prompted, and you will see real-time dBFS readings immediately. Your audio data is processed locally on your device and is never sent to any server. The tool works on both desktop and mobile browsers that support the Web Audio API.

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Free Online Decibel Meter — Measure Sound Levels in Your Browser