Decking Board Calculator
Enter your deck dimensions and board size to get the rows, total linear feet to buy, and pounds of screws, with waste built in.
Direction the boards run.
5/4x6 and 2x6 boards are 5.5 in actual.
1/4 in is standard for dry lumber; kiln-dried composite per spec.
Board rows
26
Total decking
458 linear ft
Deck screws
4 lb
26 rows across the 12 ft width. Buy 458 linear ft total, for example 29 boards at 16 ft. Screws figure 2 per joist crossing (676 total, about 175 screws per lb of #10 x 2.5 in).
How the math works
The number of rows is the deck width divided by one board width plus one gap, rounded up, since a partial row still requires a full board ripped to width. Total material is rows times deck length, plus your waste factor for cutoffs and culled boards.
Screws count two per joist crossing. Crossings per row are the deck length divided by joist spacing plus one for the end joist, and the total converts to pounds at roughly 175 screws per pound for #10 x 2.5 inch deck screws.
FAQ
- How many deck boards do I need for a 12x16 deck?
- With 5.5 inch boards and a 1/4 inch gap, a 12 foot deck width takes 26 rows. Running 16 foot boards, that is 26 boards, or about 458 linear feet with 10 percent waste included.
- What gap should I leave between deck boards?
- About 1/4 inch for drainage on dried lumber. Wet pressure-treated boards are often installed tight because they shrink to a gap as they dry. Composite decking specifies its own gap, typically 3/16 to 1/4 inch, in the install guide.
- How many screws per deck board?
- Two screws at every joist crossing. On 16 inch joist spacing, a 16 foot board crosses 13 joists, so 26 screws per board. Use coated or stainless deck screws rated for treated lumber.