Enter the real dimensions of your deck and the boards you plan to buy. The calculator counts board rows, handles spacing and direction, compares practical stock lengths, shows seams and purchase overage, and adds your chosen contingency.
Board rows, stock purchase quantity and a representative seam.
Enter your project and compare the selected stock lengths.
| Length | Boards | Seams | Overage |
|---|
The first step counts how many installed rows are needed across the deck using the actual board width plus the gap. The purchase quantity is calculated afterward from the run length, available stock lengths, saw kerf, trim, practical seam pieces and contingency.
That distinction matters on decks where one installed row needs more than one stock board, or where repeat offcuts can be reused across other rows.
Nominal names can differ from the board's installed face width. Use the actual product dimension.
Turning the boards changes both the number of rows and the length each row must cover.
Different stock lengths can change the number of seams, how offcuts are reused, and the final purchase overage.
Yes. You choose the contingency percentage. The calculator also separately accounts for stock-length cutting, so the contingency is not being used as a substitute for cut planning.
No. When the deck run is longer than the selected stock board, the engine builds a practical multi-piece row and packs repeat cuts into stock boards.
You can use the quantity math with the actual board width, gap and stock lengths for the product. Installation rules, approved gaps, fasteners and minimum supported piece lengths still need to be checked against that manufacturer's instructions.
No. It is for decking material planning. It does not size beams, posts, footings or structural joists, and it does not replace local building-code requirements.
Take the same board-planning logic and add your local board prices, fastener packs, tax and optional project costs.