dBFS

dBFS stands for decibels relative to full scale. It is a unit used in digital audio to express the level of a signal with reference to the maximum amplitude that can be represented without clipping in a given system.

In digital systems, full scale is the largest representable sample value. The level expressed in dBFS is defined as 20 log10(|V|/VFS), where V is the instantaneous amplitude and VFS is the full-scale amplitude. By convention 0 dBFS corresponds to the clipping threshold; values below are negative.

dBFS is an absolute scale tied to the digital domain, unlike analog dB scales such as dB SPL or dBu. It is used to specify headroom, monitor levels, mixing, mastering, and to prevent digital distortion in DAWs, recorders and converters.

Bit depth determines practical dynamic range; for example, 16-bit offers about 96 dB of dynamic range, 24-bit about 144 dB. Since full scale is fixed, more bits give more room before reaching 0 dBFS, reducing the risk of digital clipping in complex digital processing.

In practice, engineers often aim for peaks below 0 dBFS, commonly around -6 dBFS on a master bus, and rely on loudness normalization later in the chain. dBFS does not measure perceived loudness; LUFS or sones are used for that.