Calculate siding squares, trim and corner posts for an exterior wall.
Siding is sold by the square regardless of the metric area measured, so the conversion is the first step. Corner posts and trim are linear items priced separately from the field material. Trim and corner posts often approach a third of siding cost, so estimating only the field area understates the job substantially.
Siding
One siding square covers 100 square feet, or 9.29 m²
One siding square covers 100 square feet, or 9.29 m² Siding is sold by the square regardless of the metric area measured, so the conversion is the first step. Corner posts and trim are linear items priced separately from the field material.
Trim and corner posts often approach a third of siding cost, so estimating only the field area understates the job substantially.
This calculator takes 5 inputs: Total wall area, Windows and doors to deduct, Outside corners, Wall height, Waste allowance. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.