dB Conversion Calculator — dBu, dBV, dBFS, dBm & Voltage

dBu uses a reference voltage of 0.7746V (the voltage that produces 1 mW across 600 ohms). dBV uses a reference of 1V. 0 dBu = -2.2 dBV. Professional equipment typically operates at +4 dBu (1.228V), while consumer gear uses -10 dBV (0.316V).

dBFS (decibels relative to full scale) is the digital audio scale where 0 dBFS is the maximum level before clipping. The relationship to dBu depends on the converter's headroom setting — typically +18 dBu or +24 dBu corresponds to 0 dBFS.

dBm is a power measurement referenced to 1 milliwatt. It is commonly used in RF and telecommunications. 0 dBm = 1 mW. In audio, dBm was historically used with 600-ohm systems but has largely been replaced by dBu.

+4 dBu (approximately 1.228V RMS) was chosen as the professional operating level because it provides a good balance between headroom and signal-to-noise ratio in analogue equipment. It sits well above the noise floor while leaving sufficient headroom before clipping.