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LUFS Loudness Meter
Measures integrated loudness to ITU-R BS.1770 with K-weighting and full gating, and compares it against streaming targets.
Video & Audio
Nothing uploaded
No sign-up
Free, unlimited
Drop an audio filemeasured in this page — nothing is uploaded
Add a file to begin.
In short
LUFS is not average volume. ITU-R BS.1770 specifies a K-weighting filter that models how the ear responds — discounting deep bass, which contributes energy without contributing much loudness — then measures 400 ms blocks at 75% overlap, and then gates twice: blocks below −70 LUFS absolute are discarded, and so is anything more than 10 LU below the mean of what remains. That gating is why a track with quiet passages does not read quiet, and it is the step simple meters skip, which is how they end up disagreeing with every platform. Streaming targets sit around −14 LUFS for Spotify, Amazon and YouTube and −16 for Apple Music.
How to use the LUFS Loudness Meter
- Drop the master in.
- Read the integrated figure against the platform table.
- Aim near the target rather than as loud as possible.
About the LUFS Loudness Meter
The LUFS Loudness Meter measures integrated loudness to ITU-R BS.1770 with K-weighting and full gating, and compares it against streaming targets. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Checking a master against streaming targets before release.
- Finding out why a track is turned down on Spotify.
- Meeting a broadcast delivery specification.
Details
| Standard | ITU-R BS.1770, as used by EBU R128 |
|---|---|
| K-weighting | A shelf plus a high-pass, modelling the ear |
| Blocks | 400 ms at 75% overlap |
| Gating | −70 LUFS absolute, then 10 LU below the mean |
| Spotify, Amazon, YouTube | About −14 LUFS |
| Apple Music | About −16 LUFS |
| Broadcast | −23 LUFS in Europe, −24 in the US |
The K-weighting filters are designed for the file's own sample rate rather than using the published 48 kHz constants. Those constants are only correct at 48 kHz, and applying them to 44.1 kHz material — which most music is — shifts the answer by a few tenths of a LU.
Where this tool stops
Integrated loudness and an approximate loudness range. Short-term and momentary meters, and true-peak measurement, are separate jobs that need a live display or oversampling respectively.
Frequently asked questions
Why is my loud master turned down?
Because every streaming platform normalises. A track mastered at −6 LUFS is turned down by about 8 dB to reach a −14 target, so all the loudness gained by squashing it is removed — and what is left is a track with less dynamic range than one mastered at the target in the first place. Loudness normalisation ended the loudness war; mastering louder now costs dynamics and gains nothing.
Why does this disagree with a meter I used before?
Usually gating. A meter that averages every block, including the silences and the quiet intro, reads several LU lower than one that follows the standard. The gate is what makes the measurement about the loud parts people actually hear, and skipping it is the commonest shortcut.
Is this true peak?
No, and the difference matters. This reports the highest sample; true peak needs four-times oversampling to catch peaks that occur <i>between</i> samples, which can be 1 to 2 dB higher and clip a lossy encoder. That is why mastering engineers leave a dB of headroom rather than pushing to 0.
Is the LUFS Loudness Meter free, or is there a paid tier?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Does anything I enter leave my computer?
No. The LUFS Loudness Meter runs entirely in your browser using JavaScript. Because the work happens locally, the page also keeps working if your connection drops, and closing the tab is all it takes to discard everything.
What problem does the LUFS Loudness Meter solve?
The jobs it is built for: checking a master against streaming targets before release. Finding out why a track is turned down on Spotify. Meeting a broadcast delivery specification. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Where does the LUFS Loudness Meter stop being reliable?
Integrated loudness and an approximate loudness range. Short-term and momentary meters, and true-peak measurement, are separate jobs that need a live display or oversampling respectively. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the key numbers for the LUFS Loudness Meter?
Standard is ITU-R BS.1770, as used by EBU R128. K-weighting is A shelf plus a high-pass, modelling the ear. Blocks is 400 ms at 75% overlap. These are printed on the page itself, so you do not have to take them on trust.
Will a big file be rejected?
There is no limit set by us, because your file is never uploaded — the only ceiling is the memory your own browser will give the tab. Very large files simply take longer to process, and a phone will give up sooner than a desktop.
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