Free Loudness Meter
Loudness Meter measures integrated, short-term and momentary loudness in LUFS, true peak and loudness range, following ITU-R BS.1770-4 and EBU R128. A table shows how Spotify, YouTube, Apple Music, podcasts or broadcast would adjust the level. Normalize to a target with an optional true-peak limiter and download WAV or MP3.
- Standards:
- ITU-R BS.1770-4, EBU R128
- Accuracy:
- ±0.1 LU on EBU test cases
- Targets:
- 9 presets plus custom
- Price:
- Free
- Runs:
- Locally, in your browser
- Uploads:
- None: files never leave your device
- Account:
- Not needed
Quick answers
What is LUFS?
Loudness Units relative to Full Scale: a measure of perceived loudness defined by ITU-R BS.1770. One LU equals one decibel, so a track at −10 LUFS is 4 dB louder than one at −14 LUFS.
What loudness should I master to for Spotify or YouTube?
Both normalize playback to about −14 LUFS integrated with a true peak of −1 dBTP. Louder masters are simply turned down, so there is no advantage in going much louder.
Processed on your device: your files are never uploaded. How it works
Network activity in this tab
What this page has requested since you opened the site in this tab. An upload is any request that sends data: POST, PUT, PATCH or a request with a body.
No uploads: nothing has been sent from this page.
No network requests yet.
To see every request, open your browser's developer tools (Network tab).
How to use the Loudness Meter
- Drop an audio or video file (or switch to Live microphone).
- Read integrated loudness, true peak, loudness range and the momentary / short-term graph.
- Check the platform table to see how much Spotify, YouTube, Apple Music or broadcast would turn the track up or down.
- Pick a target and true-peak ceiling, then Normalize and download the result as WAV or MP3.
Credits & open source
Our own code plus open-source libraries. Thank you to the people who make these projects.
- MediabunnyReads, writes and converts media files with WebCodecs (MP4, WebM, MKV, MOV, MP3, WAV, Ogg...). © Vanilagy and contributors · MPL-2.0
- lamejsMP3 encoder (port of LAME), loaded as a separate unmodified chunk. © LAME project; JavaScript port by Alex Zhukov; ESM fork by Breezystack · LGPL-3.0
Web platform APIs used: Web Audio API, Media Capture (getUserMedia), Canvas 2D, File API, localStorage.
Full license texts: third-party notices · all credits
Frequently asked questions
What is the difference between true peak and sample peak?
Sample peak is the largest sample value. The real analog waveform can peak between samples; true peak estimates that by oversampling 4 times, and it is what delivery specs limit.
What does loudness range (LRA) mean?
It is the spread between the quiet and loud parts of a programme (10th to 95th percentile of short-term loudness), per EBU Tech 3342. Pop music is often 4–8 LU, film and classical can exceed 15 LU.
Is my audio uploaded?
No. Decoding, measuring and normalizing all happen in your browser.