Inverter Efficiency Calculator

Compare inverter input and output power to find efficiency and losses.

About Inverter Efficiency Calculator

Peak efficiency is quoted on datasheets but weighted efficiency across the load range matters more, because inverters spend most time well below full output. Two percentage points of inverter efficiency compounds into hundreds of kWh a year on a typical domestic array.

Formula

Inverter Efficiency

Efficiency = output power ÷ input power × 100

European efficiency: Weighted average across load levels, more representative than peak

Worked example

With the default values below, Inverter Efficiency Calculator returns Inverter Efficiency of 94.845%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Output powerminimum 0 W: 4,600 W
Input powerminimum 0.01 W: 4,850 W
Operating hours per dayaccepts 0–24 h: 8 h
Energy value per kWhminimum 0: 0.15

Results

Inverter Efficiency: 94.845%
Losses: 250.00 W
Annual Energy Lost: 730.00 kWh
Annual Value of the Losses: $109.50
Rating: Acceptable but dated

Step by step

1Values used
2Inverter Efficiency
3Inverter Efficiency= 94.845
4Losses= 250.00 W
5Annual Energy Lost= 730.00 kWh
6Annual Value of the Losses= 109.50
7Rating= Acceptable but dated

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Inverter Efficiency calculated?

Efficiency = output power ÷ input power × 100 Peak efficiency is quoted on datasheets but weighted efficiency across the load range matters more, because inverters spend most time well below full output.

Why does Inverter Efficiency matter?

Two percentage points of inverter efficiency compounds into hundreds of kWh a year on a typical domestic array.

What values do I need to enter?

This calculator takes 4 inputs: Output power, Input power, Operating hours per day, Energy value per kWh. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.