Two taps: pick your wall width, then the style. You get how many boxes or panels, their exact size, the gaps and how much moulding to buy.
More options: exact size, height, gaps, cm
Measure each wall, or each flat run between a corner, door or window, on its own. Heights are from the floor to the top of the chair rail or cap. We assume a 5 1/2 in (14 cm) baseboard and a 2 1/2 in (6 cm) chair rail.