Loudness Check
See how loud your video is, and how YouTube will play it
Drop a video or audio file: its integrated loudness in LUFS, its peak, and how far it is from the -14 LUFS YouTube plays at, with what to do about it.
Free. Works in any browser, on a phone or a computer. What you put here stays on your device.
About Loudness Check
What it measures
- Integrated loudness, the way ITU-R BS.1770 defines it and broadcasters and YouTube measure it: the whole file, K-weighted, with silence and the quietest stretches gated out. In LUFS.
- The peak: the loudest sample, in dBFS. The true peak between samples can be a little higher.
- The gap from -14 LUFS, and what YouTube does with it.
The meter is Sucia Studio's: the same code its Ready for YouTube button runs.
YouTube's rule, as far as it is published
YouTube says that stable volume is on by default and balances the range between quiet and loud. The level it plays at is not on a YouTube help page: -14 LUFS is what people measure, and the gap shows on any video under Stats for nerds (right-click the video) as the content loudness. A louder upload is turned down to that level; a quieter one is not turned up, which is why a quiet video stays quiet.
What a browser can read
- MP3, WAV, AAC and M4A, Ogg and FLAC files, and the sound of MP4, WebM and MOV videos the browser can play. MKV usually not: remux it to MP4 in OBS first (File, Remux Recordings).
- The whole file is decoded into memory, so a very long file may not fit: the page refuses files over 2 GB and warns above 500 MB. For a long stream, measure the exported edit, or a shorter cut.
How to use it
- Drop the file on the page, or choose it. It is read on this device; nothing is uploaded.
- Wait for the figures; a one-hour file takes a little while.
- Follow the line under them: raise or lower by that many decibels in your editor, with a limiter if you raise it. In Sucia Studio, Ready for YouTube does it in one press.
Rules as read on October 9, 2026 from YouTube Help: Control video volume on your device, Frame.io Workflow Guide: Loudness for YouTube, ITU-R BS.1770-5: Algorithms to measure audio programme loudness and true-peak audio level.
Questions
- Why is my video quiet on YouTube?
- Because it was uploaded quiet. YouTube turns loud videos down to its level but does not turn quiet ones up. Loudness Check says how many decibels to raise it by.
- Should I make it louder than -14 LUFS?
- There is no gain in it: YouTube turns it back down. Aim at -14 LUFS with peaks under -1 dB, and spend the effort on the mix instead.
- What is LUFS?
- Loudness units relative to full scale: a measure of how loud a whole programme sounds to a listener, not how high its peaks go. Two videos at the same LUFS sound equally loud.
- Is my file uploaded?
- No. It is decoded and measured in your browser.