About this calculator
Estimate deck board quantity from deck size, board dimensions, spacing and waste.
Real layouts, joins and border boards can change quantity.
Formula
Approximate board coverage = (board width + gap) × board length. Boards = deck area ÷ coverage × waste allowance.
Example
Use 10–15% waste for straightforward layouts unless your plan needs more.
Accuracy
NUMTX shows the assumptions next to the calculation so you can replace defaults with values that match your situation. For measurements, supplier rates, fees, interest, tax or regulated work, confirm important figures with the appropriate official or professional source.