How Many Boards for a 10x10 Deck?
Deck boards to buy
11 20 ft boards
100 square feet, 21 rows of decking, joists 16 inches on center.
When the figures look right, the deck material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.
How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Deck length10 ft
- Deck width10 ft
- Board face width5.5 in
- Gap between boards0.25 in
- Board length you buy20 ft
- Joist spacing on center16 in
Deck boards to buy11 20 ft boards
| Deck area | 100 sq ft |
|---|---|
| Board rows across the width | 21 |
| Linear feet of decking | 210 lf |
| Boards at 20 ft | 11 |
| Joists at 16 in on center | 9 |
The material list this produces
| Deck boards, 20 ft | 11 |
|---|---|
| Joists, 10 ft | 9 |
| Joist hangers, each | 18 |
| Deck screws, lb | 3 |
Board length compared
Same deck, four board lengths.
| Board length | Deck boards to buy |
|---|---|
| 8 ft boards | 27 8 ft boards |
| 12 ft boards | 18 12 ft boards |
| 16 ft boards | 14 16 ft boards |
| 20 ft boards | 11 20 ft boards |
What else matters here
Twenty one rows at 10 feet is 210 linear feet, which is eleven 20 foot boards cut in half. In 10 foot stock it is 21 boards, one per row.
What this calculator assumes
- A nominal 2x6 board is 5.5 inches of actual face. Nominal sizes are not real sizes, which is where most deck orders go wrong.
- Joist count is the span across the deck width at the spacing given, plus one for the last joist.
- Waste is not added. Add 5 to 10 percent if the deck is not a plain rectangle.
Questions people ask
How many boards for a 10x10 deck?
Eleven boards of 5/4 by 6 at 20 feet cut in half, or twenty one at 10 feet.
How many joists for a 10x10 deck?
Nine at 16 inches on center, each one 10 feet long, plus the rim joists.
The deck calculator takes any dimensions you like and hands back the same list.