Decking Calculator

Calculate deck boards, joists, posts, and hardware. Get a complete material list with cost estimates.

Enter Deck Dimensions

Deck Length(ft)

Deck Width(ft)

Board Length

Joist Spacing

Deck Height(ft off ground)

Waste factor

How to Calculate Decking Materials

Deck boards are typically 5/4x6 lumber (5.5" actual width). Divide the deck width by 5.5 inches to get the number of rows, then figure how many boards per row based on board length. Joists run perpendicular to deck boards, spaced 16" on center (or 12" for composite decking). Posts are typically spaced every 6 feet along each beam line.