Inverter Efficiency is the ratio between output power to the input power.

However you can find out your inverter efficiency in the datasheet or manual, but in some cases you have to measure that by yourself, for example when you make a DIY inverter.

**There are 3 types of efficiency:**

**1-European Weighted Efficiency**

In this type we have to measure the inverter efficiency in 6 different loads power level then using following formula

**2- California Energy Commission**

**Weighted Efficiency**

In this type we have to measure the inverter efficiency in 6 different loads power level then using following formula

**3- Peak / Maximum**

**Efficiency**

In this type we have to measure the inverter efficiency at many different loads power level as possible to see at which output power the inverter achieve max efficiency.

There are no formula for it.

In This Video i explained How to measure inverter Efficiency in details by measuring the efficiency of my 300W Inverter.