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Design Tool

DC:AC Ratio (Inverter Load Ratio) Calculator

Calculate the ratio of entered array DC capacity to inverter AC rating, without prescribing an unsupported design band.

Sources listedReviewed July 2026Our methodology

Inputs

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Total panel capacity.

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DC:AC ratio

1.32

Assessment

The entered array DC capacity is greater than the inverter AC rating. Check the exact inverter limits and model clipping with site-specific design data.

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Key takeaways
  • The DC:AC ratio (inverter load ratio) divides the array's DC capacity by the inverter's AC rating.
  • A ratio above one means the entered array DC capacity exceeds the inverter AC rating.
  • Clipping is possible when available DC power exceeds inverter output, but the correct design requires model- and site-specific checks.

How it works

The DC:AC ratio, also called the inverter load ratio (ILR), is simply the array's DC capacity divided by the inverter's AC rating:

DC:AC = array (kWp) ÷ inverter (kW)

A ratio above 1.0 means the array is “oversized” relative to the inverter. That can introduce clipping when available DC power exceeds the inverter output. The permitted and useful ratio depends on the exact inverter documentation, module arrangement, connection requirements and site-specific generation profile. This tool reports the ratio; it does not prescribe a design range.

Estimates only: for guidance, not a quote or a compliance certificate. Verify against the current AS/NZS standards and a licensed design. The maths runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately save the result.

Source ledger3 sources

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Frequently asked

Is this calculator free to use?
Yes. The DC:AC ratio calculator is free and needs no sign-up. It runs entirely in your browser.
Is my data stored or sent anywhere?
The calculation runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately select Save result.
What DC:AC ratio should I use?
There is no universal ratio for every inverter and site. Confirm manufacturer limits, connection requirements and site-specific clipping before choosing a design.
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