LUFS Loudness Meter

Overview

A loudness meter built to ITU-R BS.1770-4 and tested against the EBU's reference signals to within 0.1 LU. Drop a file and you get integrated loudness, loudness range, momentary and short-term graphs over time, and true peak measured with 4× oversampling. True peak is the number that tells you whether a master will clip once it's encoded, which a sample peak reading can't.

Check a master before releaseSee integrated loudness and true peak against the platform you're delivering to.
Compare a mix with a referenceMeasure both and see loudness and range side by side.
Deliver to broadcastMake sure a programme meets EBU R128 at −23 LUFS before you send it.

Guides

01 How to measure loudness to a broadcast target 02 How to make background music for a video

Set

Audio Tools 17

Neighbours

01 Audio Transcriber 02 Generate AI Music 03 Audio Converter 04 BPM Detector 05 DJ Booth 06 Extract Audio from Video

Specification

Command: audio.lufs_meter
Set: Audio
Input: MIXED
Output: —
Max file: 1GB
Batch: single file

MPEG WAV FLAC MP4 OGG OPUS AAC WEBM

Runtime

Engine: ffmpeg-wasm 0.12
Threads: — workers
Isolated: —
WebGPU: —
Memory: —

Transport 0 B

Your file is opened, worked on and saved inside this tab. This tool has no upload step, so your file has nowhere else to go.

Keys

Search: ⌘K
Panels: ⌘1 · ⌘2
Full width: F
All keys: ⌘/

How it works

Drop a mix or master

It's decoded on your device at 48 kHz.

Read the integrated loudness

One number for the whole track, gated so silence and fades don't pull it down.

Compare with a target

Pick the platform you're delivering to and its target appears on the meter.

Frequently asked

How do I know the numbers are right?

It's tested against EBU Tech 3341 cases 1 to 6, the EBU's own reference signals, and agrees within 0.1 LU. Loudness range is checked against the four EBU Tech 3342 cases. Audio is decoded at 48 kHz so the BS.1770-4 coefficients apply exactly as published.

What is the difference between true peak and sample peak?

Sample peak is the highest sample value in the file. True peak is the highest point the actual waveform reaches between samples, and it can be higher. A master at −0.1 dBFS sample peak can go well over 0 dBTP and clip a converter or lossy encoder. You see both readings and the gap between them.

Which target should I use?

Most streaming services normalise to around −14 LUFS and turn louder masters down, so mastering much louder only costs you dynamics. European broadcast uses −23 LUFS under EBU R128. Each target is listed with its value.

Is my audio uploaded?

No. Decoding and every measurement happen in your browser.

Keys

Search: ⌘K
Panels: ⌘1 · ⌘2
Full width: F
All keys: ⌘/