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LUFS — Loudness Units relative to Full Scale — is how loudness is actually measured: not the highest peak in your file, but how loud it feels over time. It is the number every streaming platform normalizes your track to, which makes it the most consequential number on your master.
A peak meter tells you the single loudest sample in your file. Ears do not work that way: a snare hit at -1 dBFS lasting a millisecond feels far quieter than a wall of synths at -8 dBFS held for a minute. LUFS bridges that gap. Defined in ITU-R BS.1770 and adopted broadcast-wide through EBU R128, it filters the signal to approximate human hearing (quiet, bass-heavy content counts for less), then averages energy over time.
Three flavors matter. Momentary loudness looks at the last 400 milliseconds, short-term at the last 3 seconds, and integrated at the whole track, with quiet passages gated out so silence doesn't drag the average down. When a platform or a mastering engineer says a track "is" -9.5 LUFS, they mean integrated.
Streaming services turn every track to a common playback loudness so listeners don't ride the volume knob between songs. Spotify, YouTube and Amazon Music play tracks at about -14 LUFS; Apple Music sits near -16 LUFS. A master at -8 LUFS integrated is simply turned down 6 dB on Spotify — the limiting that made it loud stays audible, the loudness advantage does not.
That is the practical meaning of the targets: they are playback levels, not commandments for your master. Mastering at exactly -14 LUFS is not required and often not ideal — but mastering far louder buys nothing on normalized playback and costs dynamics everywhere.
As loud as the music wants, knowing what normalization will do. Dense club music routinely masters between -9 and -7 LUFS because that density is the aesthetic and it must also work in unnormalized contexts — DJ sets, cars, clubs. Dynamic singer-songwriter material often lands between -14 and -11 LUFS. The useful question is not "what number should I hit" but "how does my track sound at the level everyone will actually hear it" — which you can measure instead of guessing.
Related numbers worth knowing: true peak (dBTP) caps how hot your file can safely get, and LRA describes how much the loudness moves within the track.
Upload your master and get integrated LUFS, true peak, and the exact gain each platform will apply — plus versions rendered for every target.
Check my master's LUFS — freeThere is no required number. Spotify plays your track at about -14 LUFS either way. Master for the sound you want, keep true peaks at or below -1 dBTP, and check how the normalized version sounds — that's the version listeners get.
They share the scale (1 LU = 1 dB) but measure different things. dBFS measures signal level against digital full scale at an instant; LUFS measures perceived loudness averaged over time with hearing-weighted filtering.
Spectral balance and density. A track whose energy sits in the midrange, with few gaps, feels louder than a bass-heavy or sparse one at identical integrated loudness. That's a mix decision, not a limiter setting.
No. Spotify users can switch it off, DJ software ignores it, and vinyl has no concept of it. Masters that only work at one playback gain are fragile — measure both readings.
What -14 LUFS playback does to your master.
Inter-sample peaks, dBTP, and the -1 dBTP ceiling.
Loudness range: how much a track breathes, in LU.