Solar Inverter Sizing Calculator

About this calculator

An inverter's kW rating is chosen relative to the solar array's DC capacity using a DC:AC ratio, typically between 1.1 and 1.3 — meaning the panels can generate somewhat more DC power than the inverter can convert to AC at once. This intentional oversizing is not a mistake: panels rarely hit their full rated output in real conditions, so a modestly undersized inverter captures more usable energy across low-light hours at the cost of a small amount of "clipping" — lost power — only during the very peak of sunny days.

Solar installers and DIY system designers use this ratio to pick an inverter that matches the array rather than one sized 1:1 to panel wattage, since an inverter that is too small clips excessively and one that is too large is needlessly expensive and never runs near its rated capacity.

This calculator takes your solar array's DC kW rating and desired DC:AC ratio and returns the inverter kW rating you need, so you can size your system the way a professional installer would rather than defaulting to a 1:1 match.