Decking Calculator
Divide the deck width by your board width plus a 1/4-inch gap to count board rows running the full deck length, apply waste, and count joists at your chosen spacing plus one end joist. Boards are assumed to span the deck without butt joints.
Decking Calculator
Divide the deck width by your board width plus a 1/4-inch gap to count board rows running the full deck length, apply waste, and count joists at your chosen spacing plus one end joist. Boards are assumed to span the deck without butt joints.
Method and assumptions
Figur turns your measurements into purchase quantities with standard geometry: it computes the area, length, or volume, applies the waste or spacing you enter, and rounds up to whole purchase units. Everything is calculated locally in your browser.
- Purchase quantities round up to whole units (sheets, bundles, boards, bars, or packages) because suppliers do not sell fractions.
- Assumed coverages and package sizes (for example, 3 bundles per square or 4×8 sheets) are common conventions; verify your product label and supplier.
- The waste percentage is applied exactly as entered; complex cuts, patterns, and damage can require more.
- The result does not replace your field measurements, plans, or local code requirements.
This tool provides a planning takeoff, not a binding bid, structural design, or engineering advice. Confirm quantities with field measurements, your supplier, and the applicable professionals before buying.
Sources and references
No external data source is required: this calculator applies standard geometry to the measurements, coverages, and waste you enter.
Frequently asked questions
What board length does this assume?
Each counted board runs the full deck length in one piece. If your deck is longer than available boards, plan butt joints over joists and expect the waste percentage to matter more.
Does the joist count include beams and posts?
No. Joists are counted at your spacing across the deck length plus one closing joist. Beams, posts, footings, blocking, and hardware depend on your framing plan and local code.