This tool converts from dBu to dBm.

**Formula**

**dBm = dBu + 27.78 – 10*Log _{10}(Z)**

where Z is the impedance in ohm (Î©)

**Example Calculations**

A value of 0 dBu is equivalent to 10.79 dBm or 0.012 Watt.

**Background**

**What is dBu?**

**dBu is the RMS voltage relative to 0.7746 Volt. **

1 V_{RMS} is therefore equivalent to 20*Log_{10}(1/0.7746) = 2.218 dBu.

The inverse relationship or conversion from dBu to V_{RMS} is defined by the formula V_{RMS} = 10^{(dBu / 20)} x 0.7746.

**Notes: **

- dBu is different from dBV which is the RMS voltage relative to 1 Volt.
*dBV to dBm Calculator.* - dBu is also not the same as dBuV or dBÂµV which is the RMS voltage relative to 1 microvolt.
*dBÂµV to dBm Calculator.*

**Where does 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 = âˆš(600Î© * 0.001W)** **Volt**

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

**What is dBm?**

**dBm stands for deciBel referenced to 1 milliwatt**. It is an absolute unit of power and thereâ€™s an easyÂ conversion from Watt to dBm.

**P _{dBm} = 10*log_{10}(1000*P_{W})**

where

**P**is the power expressed in watt._{W}**P**is the power expressed in dBm_{dBm}

**Related Posts**

- dBm vs dB – how are they different?
- dBm average power calculator – you can’t add dBm as you would add linear quantities
- dBm to dB converter – how and when does it make sense?