Calculate how many siding boards you need for an exterior wall, based on wall measurements, board width and standard board length.
The calculator first finds how many horizontal rows are needed to cover the wall height, then works out the total number of boards based on the standard board length:
If you're using horizontal siding (the most common), the boards run horizontally and "rows" means the number of boards stacked in height. If you're using vertical siding, swap length and height in the calculation.
Horizontal siding (lap siding) is installed horizontally with overlap, while vertical siding (board-and-batten) is installed vertically. The installation method affects how you should enter length and height in the calculator.
This calculator doesn't automatically subtract area for openings. If they're large, you can reduce the wall area manually. For smaller openings, it's often easier to just account for a bit of extra waste.