How many deck boards for a 10x12 deck?
You need 22 deck boards at 12 ft long.
That is 22 rows across the 10 ft span, or 264 linear feet. Buy 291 linear feet to cover the usual 10% for cuts and defects.
A 10x12 deck by the numbers
| Deck area | 120 sq ft |
|---|---|
| Rows of decking | 22 |
| Board length | 12 ft |
| Boards to buy | 22 |
| Decking | 264 linear ft |
| With 10% waste | 291 linear ft |
| Joists at 16 in on centre | 10 |
| Footings | 9 |
| Deck screws | 588 |
Where that number comes from
- 10 ft across × 12 = 120 in to cover
- 120 ÷ 5.625 = 21.3 rows, rounded up to 22
- 22 rows × 12 ft long = 264 linear feet
- Add 10% for cuts and culls = 291 linear feet
Boards run the length of the deck here, so the 12 ft dimension sets board length and the 10 ft dimension sets how many rows you need. Running them the other way swaps the two numbers.
Working to a different size? The calculator takes any dimensions and returns the same figures.
Cutting a 10x12 out of stock lengths
The 12 ft run lands exactly on a 12 ft board: 22 boards, 22 rows, nothing cut and nothing left over. Why running them the other way changes the order.
Nothing longer divides into 12 ft — the next stock size up is 16 ft, which would leave an offcut too short to use as a row. Buy 22 boards at 12 ft and cut nothing.
Order 291 linear feet, not the bare 264 — about 2 spare rows on a 10x12. What the cull rate covers.
Before you order: getting a decking order right.
Other deck sizes
Deck calculator for any size, or all calculators.