Updated October 2026 · Levels and metering explained
Decibels measure the level of a signal relative to a reference, while loudness units measure how loud a sound is perceived to be, using a model of human hearing. Loudness is measured in LUFS and LU, which are related to decibels but weighted for perception. Use decibels for setting levels and loudness units for matching how loud a file sounds.
Audio meters show two kinds of unit that look similar and mean different things. Decibels measure the level of a signal against a reference. Loudness units measure how loud a sound is perceived to be, using a model of how the ear responds to different frequencies. Confusing them leads to mistakes, such as setting a level by the wrong meter or judging a file by a number that does not describe what the listener hears.
This post explains the difference between the two, why loudness uses its own scale and how to use both when you set levels and check a finished file.
A decibel is a ratio on a logarithmic scale. In recording, the level is usually shown in dBFS, which compares the signal with the maximum the system can store. Decibels describe how strong the signal is at a particular point, which is ideal for setting gain and avoiding clipping. They do not account for how the ear hears different frequencies.
Loudness units, written as LU, and the loudness scale LUFS, measure perceived loudness. The measurement applies a weighting that reflects how sensitive the ear is at different frequencies, and it averages the result over time. Two signals with the same peak level can have very different loudness, and the loudness scale reflects that difference.
Loudness is measured from the same digital signal as the decibel level, but it adds the perceptual weighting and the averaging. So a loudness reading is always in relation to the level of the signal, but it is not the same number. A file can have a peak at minus three decibels and a loudness far lower or higher, depending on its content.
A loudness meter usually shows an integrated value for the whole file, a short-term value for recent sound and a momentary value for the last fraction of a second. The integrated figure is the one most often matched to a target. The true peak, shown separately, tells you whether the file will clip on playback.
A beginner may see minus 14 on a loudness meter and think the file is too quiet, because it looks like a small negative number. Loudness targets are usually negative numbers below full scale, and a higher number is louder, not quieter. Another confusion is treating a loudness reading as a peak reading. They answer different questions.
Many beginners find loudness numbers counterintuitive, because a larger number on a level meter usually means louder, while many loudness targets are negative. A target of minus fourteen is louder than minus twenty, even though the number is smaller. The easiest way to avoid confusion is to say the target in full, such as minus fourteen LUFS integrated, and to remember that the scale is measured from full scale downward.
Write the target at the top of your project notes, with the standard it refers to. A clear label removes most of the confusion, especially when you return to a project after a break.
When you share a file with a collaborator, state its loudness and the standard used. A bare number without a unit is easy to misread, and a misread target can lead to a file that is too quiet or too loud for its destination.
When you receive a file from someone else, check its loudness and true peak before you edit it. A file that arrives very quiet may have been mixed for a different purpose, and raising it may bring up noise and room tone. A file that arrives very loud may already be limited, and reducing it may not restore the dynamics that were lost. Measure first, then decide what changes are sensible.
Ask the sender what the file is for and what loudness it was intended to reach. A short exchange at the start saves rework, and it makes the final delivery easier to agree.
Loudness standards and the targets used by platforms change over time, so check the current guidance from the platform you publish to. The principles here apply broadly, but the specific numbers belong to the standard in use.
Checking both kinds of reading on the export gives the most reliable result. The LUFS meter shows the loudness and true peak of a finished file, and the LUFS meter guide explains how to read the readings. For the decibel basics, see the decibels post in this series.
Integrated LUFS, true peak and streaming targets. Runs in your browser, nothing is uploaded.
No. Loudness units weight the level for how the ear hears, while decibels measure the signal itself.
Not necessarily. Loudness targets are negative numbers, and the value describes the target level, not a fault.
The peak reading, in decibels or true peak. Loudness does not show clipping.
Loudness, so that files sound similarly loud when played one after another.
