Solar DC/AC ratio calculator
The DC/AC ratio (inverter loading ratio) is your total module power divided by your total inverter power. See where your design sits, and how many modules match a target ratio.
Result
The module count is before string sizing. You still need to fit the inverter's MPPT voltage window and string length, so adjust by a module or two.
What the DC/AC ratio means
Modules rarely deliver their rated power. Heat, lower sunlight, dirt and wiring losses keep them mostly under 80–90% of rated. So an inverter a bit smaller than the array loses little energy and costs less.
Too high
On clear days around noon the array can produce more than the inverter can pass, and the extra is cut off (clipping). At 1.1–1.3 that loss is often under 1% a year; above 1.5 it can reach several percent. South-facing, steep arrays clip more.
Too low
Below 1.0 the inverter is mostly underused. No energy is lost, but you paid for inverter capacity you do not use, and efficiency at low load is a little lower.
| DC/AC ratio | What it means |
|---|---|
| Below 1.0 | Oversized inverter, no clipping |
| 1.1–1.3 | Most common range, small clipping loss |
| 1.3–1.5 | Cheaper inverter, check clipping loss |
| Above 1.5 | Large clipping, needs an hourly simulation |
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Design for free →FAQ
What is a good DC/AC ratio for solar?
Most systems use 1.1 to 1.3. In that range clipping loss is often under 1% a year while the inverter costs less. Steep south-facing arrays are usually kept toward the lower end.
How many 440 W modules for an 8 kW inverter?
For a 1.2 ratio: 8 kW × 1.2 ÷ 0.44 kW ≈ 22 modules. Then adjust to fit the inverter's string length and MPPT voltage.
Is a DC/AC ratio above 1.5 allowed?
Often yes, if you stay within the inverter's maximum DC input. But clipping loss grows, so check it with an hourly simulation first.