For decades, loudness was judged by eye: push the peaks close to 0 dBFS and call it done. The trouble is that peaks say very little about how loud something sounds. A snare hit and a sustained synth pad can peak at the same level while one sounds far louder. LUFS fixes that.
What LUFS actually measures
LUFS (Loudness Units relative to Full Scale) comes from the ITU-R BS.1770 standard. It filters the audio to roughly match how sensitive our ears are to different frequencies — less weight on deep bass, a little more on the upper mids — then averages the energy over time. The result tracks perceived loudness far better than a peak meter.
- Integrated LUFS — the average over the whole song. This is the number streaming services use.
- Short-term (3 seconds) and momentary (400 ms) — how loud each section is right now.
- Loudness range (LRA) — how much the loudness varies between quiet and loud parts.
Why streaming changed the rules
Spotify, YouTube, Apple Music and most other platforms normalise playback: they measure each song and turn loud ones down so everything plays at a similar level. A master squashed to −7 LUFS doesn't sound louder than one at −14 once it's been turned down — it just has less punch, because its peaks were flattened to get there.
Sensible targets
- Streaming music: around −14 LUFS integrated is the common reference point.
- Apple Music: normalises to about −16 LUFS.
- Podcasts and spoken word: about −16 LUFS.
- Broadcast (EBU R128): −23 LUFS.
These are references, not rules. Plenty of great-sounding pop and electronic records sit louder than −14 on purpose. The point is to choose your loudness for the sound you want, knowing the platform will level it anyway.
Measure before you decide
Drop your track into the free LUFS meter to see its integrated loudness, true peak and loudness range, then check the loudness penalty tool to hear how each platform would play it. If a service turns your master down by several decibels, you've traded dynamics for nothing.