Plan your decking boards and budget before you build.
This estimate assumes boards run the full length of the deck in straight rows; add extra for diagonal patterns, waste, and cut-offs.
It multiplies deck length by width to get square footage, then calculates the number of boards needed based on board width and length, adding a waste allowance.
Cuts, angled edges, and board spacing gaps mean a few percent of material is typically lost, so most calculators add 10-15% extra to avoid running short.
Only if the calculator specifically asks for substructure dimensions — many deck calculators focus on decking boards only, with framing estimated separately.