Convert any audio level between dBu, dBV, dBm, dBFS and volts — RMS, peak and peak-to-peak — and see where it sits between mic level and digital full scale.

dB gain ↔ ratio

Turn a gain figure in decibels into the number it actually multiplies by — or the other way round.

How this is calculated

Every unit here is a voltage expressed in decibels against a fixed reference, so the whole page runs on one conversion: everything is turned into volts RMS first, then back out again.

dBu = 20·log₁₀(V / 0.7746) · dBV = 20·log₁₀(V / 1) · dBm = 10·log₁₀(V² / Z / 0.001)

0 dBu is 0.7746 V RMS — the voltage that dissipates exactly 1 mW in 600 Ω, which is why 0 dBu and 0 dBm are the same voltage only at 600 Ω. 0 dBV is a round 1 V, so dBV always reads 2.22 dB lower than dBu for the same signal. Peak and peak-to-peak assume a sine wave: V_peak = V_RMS·√2.

dBFS is different in kind. It has no volts of its own — 0 dBFS is simply the largest number the converter can represent, so a level in dBFS only becomes a voltage once you fix an alignment level: the analogue level your gear reaches at digital full scale. This tool defaults to +18 dBu = 0 dBFS (EBU R68, standard across European broadcast and common on audio interfaces); US broadcast generally uses +24 dBu (SMPTE RP155). Change it in the panel to match your converters and every dBFS figure moves with it.

Typical audio levels

Signal	Level	In volts RMS
Dynamic mic, speech at 30 cm	−60 to −40 dBu	0.8–7.7 mV
Electric guitar pickup	−30 to −10 dBu	24–245 mV
Consumer line level (RCA)	−10 dBV = −7.8 dBu	0.316 V
Pro line level (balanced)	+4 dBu = +1.8 dBV	1.228 V
Max output, typical interface	+18 to +24 dBu	6.2–12.3 V

dB to ratio, at a glance

dB	Voltage ×	Power ×
−20	0.100	0.010
−10	0.316	0.100
−6	0.501	0.251
−3	0.708	0.501
0	1.000	1.000
+3	1.413	1.995
+6	1.995	3.981
+10	3.162	10.00
+20	10.00	100.0

FAQ

What is the difference between dBu and dBV?

Only the reference voltage. dBu is referenced to 0.7746 V RMS, dBV to 1 V RMS, and that gap is a constant 2.22 dB: any signal reads 2.22 dB higher in dBu than in dBV. Pro audio gear is usually specified in dBu, consumer gear and test equipment in dBV.

How much louder is +4 dBu than −10 dBV?

−10 dBV is −7.78 dBu, so pro line level sits 11.8 dB above consumer line level — a voltage ratio of about 3.9×. That is why plugging a consumer output into a pro input sounds thin and noisy, and why the reverse can overload the input.

Is 0 dBm the same as 0 dBu?

At 600 Ω, yes — both are 0.7746 V RMS. At any other impedance they diverge, because dBm measures power (1 mW reference) while dBu measures voltage. Modern audio gear is voltage-driven with bridging inputs, so dBu is the meaningful unit; dBm survives mainly on older equipment and in RF work.

Why does my DAW show a different dBFS than this tool?

Because the alignment level is a choice, not a constant. If your interface reaches full scale at +24 dBu and this tool is set to +18 dBu, every reading will be off by exactly 6 dB. Check your converter's specification — it is usually quoted as "maximum input level" — and match the alignment field to it.

Why is +6 dB double the voltage but four times the power?

Power goes as voltage squared, so the same physical change is 20·log₁₀ in voltage terms and 10·log₁₀ in power terms. Doubling voltage is +6.02 dB; doubling power is +3.01 dB. It matters when you read amplifier specs — see the SPL calculator, where doubling amplifier power buys only 3 dB of loudness.

Does any of this apply to dB SPL?

The arithmetic is identical, the reference is not: dB SPL is referenced to 20 µPa of sound pressure in air, not to a voltage in a cable. There is no fixed conversion between an electrical level and an acoustic one — that depends on the sensitivity of the speaker and how far away you are standing, which is exactly what the speaker SPL calculator works out. For the cable side of the same chain, see the speaker wiring calculator.

Decibel converter