# Volt to dBu Calculator

This tool converts RMS Voltage to dBu.

In what follows we also provide an overview of what dBu and RMS voltage mean.

???? dBu to Volt

## Formula

dBu = 20*Log10(VRMS/0.7746)

## Background

### What is dBu?

dBu is the RMS voltage relative to 0.7746 Volt.

1 VRMS is therefore equivalent to 20*Log10(1/0.7746) = 2.218 dBu

The inverse relationship or conversion from dBu to VRMS is defined by the formula VRMS = 10(dBu / 20) x 0.7746.

Notes:

Where does the number 0.7746 come from?

It is the value of voltage that dissipates 1 milliwatt (mW) into a 600 ohm load. Reference: Wikipedia article on dB Voltage

V = √(600Ω * 0.001W) Volt = 0.7746 V

dBu was originally dBv, however it was changed to what it is today to avoid confusion with dBV. Wikipedia Reference.

### What is RMS Voltage?

The Root mean square (RMS) voltage is the square root of the arithmetic mean of the squares of a set of voltage values.

RMS Value Formula

The formula for this is

VRMS = √(1/n)(V12 + V22 + … + Vn2)

where VRMS is the RMS value of the sequence of numbers V1, V2 … Vn.

Use the following calculators to find VRMS from