Normalize to −14 LUFS. Or any loudness target, with a true-peak limiter. Free, in your browser, no sign-up.

LUFS (loudness units relative to full scale) measure how loud audio sounds over its whole length, weighted the way hearing is and ignoring silence. Streaming services play everything at about the same LUFS, so a track mastered louder is turned down and one mastered quieter may be turned up. Normalizing it yourself means you decide how it sounds at that level, instead of the service's turn-down or limiter deciding.

This tool measures the file's integrated loudness, applies the gain that moves it to your target, then runs a look-ahead limiter so the louder file doesn't clip. It measures again after limiting; if the limiter took loudness back, it adds the difference and limits again, so the result lands on the target.

−14 LUFS is Spotify's published reference and the level YouTube is measured to play at. Apple Music's Sound Check is measured at around −16. Podcasts usually aim for −16 LUFS; −19 is the quieter spoken-word target some platforms and broadcasters ask for.

Louder is not better on a streaming service: a master pushed to −8 is turned down 6 dB on Spotify and keeps only the squashed dynamics. If a distributor or client gives you a number, use theirs.

The tool adds at most 40 dB of gain. A very peaky file normalized to a loud target needs a lot of limiting to fit under the ceiling; if the limiter can't get within 0.5 LU of the target, the page says how close it got rather than pretending. Heavy limiting flattens drums: past a few decibels, a proper master in the studio, with compression before the limiter, sounds better.

Mono files are measured as they play, on both speakers, which reads 3 dB above a strict single-channel measurement. So a spec that asks for −19 LUFS on a mono file means the same playback level as −16 here.