Deck boards by deck size
| Deck size | Board length | Boards (with 10%) | Joists at 16 in | Screws |
|---|---|---|---|---|
| 10 × 10 ft | 10 ft | 25 | 9 | 396 |
| 12 × 12 ft | 12 ft | 29 | 10 | 520 |
| 16 × 12 ft | 16 ft | 29 | 13 | 676 |
| 16 × 16 ft | 16 ft | 39 | 13 | 910 |
All sizes assume 5.5 inch boards with a 1/8 inch gap, running the length of the deck, and two screws per board at every joist.
Choosing board length
Pick boards that span the deck without a joint where you can. On longer decks, stagger the butt joints and make sure each one lands on a joist.
Frequently asked questions
How many 2x6 boards for a 12x12 deck?
About 26 rows, so 29 boards with 10% extra if each 12 ft board spans the full deck.
How much does decking for a 12x12 deck cost?
At $25 a board, about $725 for the decking alone. Composite boards often cost two to three times more than pressure-treated pine.
Last reviewed: 2026-10-31