Leelo

Free tool

How loud is your audio, really?

Drop a file to measure its integrated loudness in LUFS, and see how it compares with podcast, streaming and broadcast targets.

What you'll get

  • Integrated loudness in LUFS, measured to ITU-R BS.1770.
  • The file's sample peak.
  • How far it is from the usual targets for streaming, podcasts, audiobooks and broadcast.

01Loudness

Why loudness is measured in LUFS.

Two files can peak at the same level and still sound very different in volume. LUFS measures loudness the way ears hear it, weighting the frequencies we're most sensitive to, and averaging over the whole programme while ignoring silence.

Platforms use it to level everything they play. If your podcast is much quieter than the one before it, listeners reach for the volume, and if it's much louder, the app turns it down, often squashing the dynamics you worked on. Delivering at the expected loudness avoids both.

Leelo masters every export to the loudness you choose: −16 LUFS for podcasts, −20 for audiobooks, −23 for broadcast, or left as generated.

02Questions

About loudness.

Loudness Units relative to Full Scale: a measure of how loud audio sounds to people, rather than how high its peaks go. It's what streaming services, podcast apps and broadcasters use to set and match volume.

Around −16 LUFS for stereo is the common target, which keeps episodes at a similar volume to everything else in a listener's feed.

YouTube and most music streaming services normalise to around −14 LUFS. Louder uploads are turned down, so there's no benefit in mastering louder.

No. The file is decoded and measured by your browser. Nothing is sent to a server.

It follows ITU-R BS.1770-4: K-weighting, 400 ms blocks and the two loudness gates. Results normally agree with professional meters to within a few tenths of a LU. It measures sample peak rather than true peak.

Get it right on export.

Leelo masters every export to podcast, audiobook or broadcast loudness, so you don't have to fix it later. 1,000 free credits to start.

Start free: 1,000 credits