Boards for a 10 × 12 ft deck, by board length
A 10 × 12 ft deck fits a dining table plus a small grill. With 5½ in boards and 1/8 in gaps the deck has 26 rows, which is 260 ft of decking before waste. These counts include 10% waste:
| Board length | Boards to buy | Total length bought |
|---|---|---|
| 8 ft boards | 36 | 288 ft |
| 10 ft boards | 29 | 290 ft |
| 12 ft boards | 24 | 288 ft |
| 16 ft boards | 18 | 288 ft |
| 20 ft boards | 15 | 300 ft |
Waste and layout
| Layout | Waste | 12 ft boards | 16 ft boards |
|---|---|---|---|
| Straight, careful installer | 5% | 23 | 18 |
| Straight (typical) | 10% | 24 | 18 |
| Diagonal or picture-frame border | 15% | 25 | 19 |
Joists and screws
Joists run the 12 ft width and are spaced along the 10 ft length.
| Joist spacing | Joists | Screws |
|---|---|---|
| 12 in on center | 11 | 572 |
| 16 in on center | 9 | 468 |
| 24 in on center | 6 | 312 |
That is just the decking surface, for a 120 ft² deck. Posts, beams, footings, ledger, railings and stairs are extra, and a permit is usually required.
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Tools & materials for this project
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Frequently asked questions
How many deck boards for a 10x12 deck?
With 5½ in boards, 1/8 in gaps and 10% waste, you need 24 boards of 12 ft, or 18 boards of 16 ft. That is 26 rows of decking across the 12 ft width.
How many joists does a 10x12 deck need?
At 16 in on center, 9 joists running the 12 ft width. At 12 in it is 11, and at 24 in 6. Joist size and span must follow your local building code.
How many screws for a 10x12 deck?
About 468 screws: two at every joist for each board. Buy a few extra, since they strip and get dropped.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.