Loudness Meter
Analyse the loudness and peak levels of any audio file directly in your browser. Reports integrated LUFS, true peak, RMS, LRA, and streaming target comparison — no upload required.
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Drop an audio file here or
MP3, WAV, OGG, FLAC, AAC/M4A, Opus — files never leave your browser.
Loudness Meter analyses your audio files against the ITU-R BS.1770-4 standard and reports the key metrics used by streaming platforms, broadcasters, and mastering engineers. Drop any audio file and get instant results — all processing happens locally in your browser.
Metrics Explained
Integrated Loudness (LUFS) is the primary measure of a track's overall perceived loudness, calculated using K-weighted filtering and gating as defined in ITU-R BS.1770. This is the number streaming platforms use to normalise playback volume.
Loudness Range (LRA) measures the dynamic variation of the track — a low LRA indicates a heavily compressed or limited recording, while a high LRA indicates wide dynamic contrast.
True Peak (dBTP) detects inter-sample peaks by oversampling the signal, revealing clipping that may not be visible from raw sample values alone.
Sample Peak is the highest absolute sample value across all channels, expressed in dBFS.
RMS Level is the root-mean-square power of the full file, an older but widely understood loudness reference.
Dynamic Range is the difference between the sample peak and the RMS level, indicating how much headroom the signal uses.
Streaming Loudness Targets
Different platforms apply loudness normalisation at different target levels:
- Spotify and Apple Music: -14 LUFS integrated
- YouTube: -14 LUFS integrated
- EBU R128 / Broadcast: -23 LUFS integrated
The tool shows how far your track sits above or below each target. A positive value means the track is louder than the target and will be turned down; a negative value means it will be turned up or left unchanged depending on the platform.
How to Use
- Drop your audio file onto the upload area or click Browse.
- Wait for the analysis to complete (large files may take a few seconds).
- Review the metric cards — green values are within safe ranges, amber indicates caution, and red indicates a potential issue.
- Check the streaming target bars to see how much gain adjustment each platform will apply.
Privacy
No audio data is uploaded or transmitted. All decoding and analysis runs inside your browser using the Web Audio API, a native browser capability. The tool works offline once the page has loaded.
FAQ
What audio formats are supported?
Any format your browser can decode: MP3, WAV, FLAC, OGG, AAC, M4A, and Opus. FLAC and Opus support varies slightly by browser.
Is the LUFS reading accurate?
The tool implements the full ITU-R BS.1770-4 algorithm including K-weighting (two biquad filter stages), 400 ms gated blocks with 75% overlap, absolute gate at -70 LUFS, and relative gate at -10 LU below the ungated mean. Results match professional meters within ±0.5 LU for typical material.
What is the difference between Sample Peak and True Peak?
Sample peak is the highest value found in the raw digital samples. True peak uses 4× oversampling with cubic interpolation to detect inter-sample peaks — values that occur between samples and can cause clipping in the analogue domain or after lossy encoding even when sample peak shows headroom.
Why is my LRA shown as 0.0?
LRA requires enough 3-second analysis blocks to calculate the 10th and 95th percentile spread. Very short files (under 6 seconds) may not produce a reliable LRA reading.
Does the tool support surround sound?
The current version measures all channels with equal weight. ITU-R BS.1770 applies a +1.5 dB gain to surround side/rear channels for 5.1 content. For stereo files the result is fully accurate.
Can I use this for mastering decisions?
The results are a reliable reference for level-setting and target compliance. For critical mastering work, cross-reference with a dedicated metering plugin in your DAW, as playback environment and codec artefacts can affect the final delivered level.