How this calculator works
The calculator multiplies deck length by deck width for square footage. It converts the deck width to inches, then divides by board face width plus the planned gap to estimate how many rows are needed. Linear feet are the board rows multiplied by board run length, then increased by the waste allowance.
Example: a 16 ft by 12 ft deck with 5.5 inch boards and a 1/8 inch gap needs about 26 board rows. At 16 ft per row, the project needs roughly 416 linear feet before waste and about 458 linear feet with 10% waste.