What Does -14 LUFS Mean on a Loudness Meter?
The short answer
-14 LUFS is an integrated loudness value: it says a program averages 14 loudness units below digital full scale across its whole duration, measured with the algorithm defined in ITU-R BS.1770. It is an average over time, not a peak reading, and not a fader position. In practice the number is usually quoted as a target — a value a delivery spec or a playback system normalizes toward — rather than a hard ceiling a file must not cross.
LUFS is an average, not a peak
A LUFS reading is produced by filtering the signal to approximate the ear's frequency response, squaring and averaging the result over time, summing the channels with defined weights, and gating out near-silence so that pauses do not drag the average down. That is the substance of the BS.1770 method published by the ITU.
Because it is an average, two files can both read -14 LUFS integrated while behaving very differently moment to moment: one dense and steady, one quiet with a few loud events. Those differences show up in the shorter measurement windows, not in the integrated number. If you want the distinction between the three windows, see momentary, short-term, and integrated LUFS.
Why -14 LUFS is not -14 dBFS
A dBFS reading is a sample-by-sample comparison against digital full scale, with no frequency weighting and no time averaging. A LUFS reading is weighted and averaged. The two scales share the same zero point in the sense that both are referenced to full scale, but they answer different questions, so the numbers do not convert.
That is why a file measuring -14 LUFS integrated can still have samples sitting close to 0 dBFS. A busy master can read -14 LUFS with peaks a fraction of a decibel below full scale; a sparse acoustic recording may need far more peak room to reach the same average. The relationship between average and peak is a property of the material, not a constant. LUFS vs. dBFS covers the two scales side by side.
LU, LUFS, and dB
One loudness unit equals one decibel in size. The suffix is what changes:
- LUFS — an absolute level, referenced to full scale.
- LU — a relative figure, a difference between two loudness readings.
So a program at -17 LUFS is 3 LU quieter than one at -14 LUFS, and a meter that shows "-3 LU" is reporting distance from whatever target it has been set to. The general rule behind this — that a decibel figure is meaningless without a stated reference — is set out in the NIST Guide to the SI.
Where loudness targets come from
Targets originated in broadcast, where program-to-program level jumps were a persistent complaint. Recommended practice documents such as ATSC A/85 pair a loudness target with a true-peak ceiling set below full scale, and specify BS.1770 as the measurement method. Music streaming adopted the same idea later, with its own target values, which is why the same track can be played back at different levels in different places. See why a track sounds quieter on streaming services.
Target values differ by use case and change over time. Treat any specific figure — -14 LUFS included — as something to read off the current delivery spec you are working to, not as a universal constant.
Reading a meter against a target
Three readings describe a file against a target:
- Integrated LUFS — the whole-program average, the number compared to the target.
- Loudness range — how widely the short-term loudness varies.
- True peak in dBTP — the estimated maximum of the reconstructed waveform, which is the figure a peak ceiling refers to. See true peak vs. sample peak.
A file can meet a loudness target and still exceed a peak ceiling, or vice versa; the two are measured separately and specified separately.