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Solar Inverter Size Calculator

Size a solar inverter for an array, including the DC to AC ratio.

About Solar Inverter Size Calculator

Deliberately oversizing the array relative to the inverter raises annual yield because peak output occurs for only a few hours a year. Ratios up to about 1.25 lose very little to clipping. Undersizing the inverter is usually more economic than matching it exactly, since inverter cost scales with capacity but peak output is rare.

Formula

Solar Inverter Size

Inverter kW = array kW ÷ DC:AC ratio

DC:AC ratio
Array capacity divided by inverter capacity, typically 1.1 to 1.3
clipping
Generation lost when array output exceeds inverter capacity

Worked example

With the default values below, Solar Inverter Size Calculator returns Inverter Size Required of 5.417. Change any input above and every figure here is recalculated in your browser.

Inputs used

Array sizeminimum 0 kW
6.5 kW
Target DC to AC ratioaccepts 0.8–2 x
1.2 x
Acceptable clipping lossaccepts 0–100 %
2 %
Grid export limitminimum 0 kW
5 kW

Results

Inverter Size Required
5.417 kW
Resulting DC to AC Ratio
1.083 x
Nearest Standard Inverter Size
6.0 kW
Export Limit Status
Inverter exceeds the export limit — export limiting will be required
Estimated Clipping Loss
0.00%

Step by step

  1. 1Values used
  2. 2Solar Inverter Size
  3. 3Inverter Size Required= 5.417 kW
  4. 4Resulting DC to AC Ratio= 1.083 x
  5. 5Nearest Standard Inverter Size= 6.0 kW
  6. 6Export Limit Status= Inverter exceeds the export limit — export limiting will be required
  7. 7Estimated Clipping Loss= 0.00

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 Solar Inverter Size calculated?

Inverter kW = array kW ÷ DC:AC ratio Deliberately oversizing the array relative to the inverter raises annual yield because peak output occurs for only a few hours a year. Ratios up to about 1.25 lose very little to clipping.

Why does Solar Inverter Size matter?

Undersizing the inverter is usually more economic than matching it exactly, since inverter cost scales with capacity but peak output is rare.

What values do I need to enter?

This calculator takes 4 inputs: Array size, Target DC to AC ratio, Acceptable clipping loss, Grid export limit. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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