DC/AC Ratio
The DC/AC ratio (also called the inverter loading ratio or clipping ratio) is the ratio of a solar PV system's total DC capacity to the inverter's rated AC output capacity. It's a key system design parameter that balances energy capture with inverter cost and performance.
DC/AC Ratio = DC System Size (kW) ÷ Inverter AC Rating (kW)
For a 13 kW DC array paired with a 10 kW AC inverter:
DC/AC Ratio = 13 ÷ 10 = 1.3
Why Oversizing DC is Economically Beneficial
Solar arrays rarely produce their rated DC power — peak production occurs for only a few hours around solar noon on clear days. An inverter sized at exactly the DC capacity would be underutilized most of the day.
By sizing the inverter smaller than the array (DC/AC ratio > 1.0), the array can feed the inverter at closer to its rated output for more hours per day, improving inverter utilization. When the array would exceed the inverter's rated input, the excess is "clipped" — a small energy loss that is more than offset by the lower inverter cost.
Optimal DC/AC Ratio
Residential (lower solar resource, moderate climate): 1.10–1.20
Commercial/utility (high solar resource, hot climate): 1.20–1.40
Higher DC/AC ratios are appropriate for high-irradiance locations where clipping hours are limited, or for sites with significant soiling and degradation over time. The optimal ratio is site-specific and should be verified through energy modeling.
In SolarScope
When configuring a project in SolarScope, enter your planned DC system size. The production estimates account for typical DC/AC ratios through the performance ratio parameter.