How Many Boards for a 5x5 Deck?
Deck boards to buy
7 8 ft boards
25 square feet, 11 rows of decking, joists 16 inches on center.
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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 length5 ft
- Deck width5 ft
- Board face width5.5 in
- Gap between boards0.25 in
- Board length you buy8 ft
- Joist spacing on center16 in
Deck boards to buy7 8 ft boards
| Deck area | 25 sq ft |
|---|---|
| Board rows across the width | 11 |
| Linear feet of decking | 55 lf |
| Boards at 8 ft | 7 |
| Joists at 16 in on center | 5 |
The material list this produces
| Deck boards, 8 ft | 7 |
|---|---|
| Joists, 5 ft | 5 |
| Joist hangers, each | 10 |
| Deck screws, lb | 1 |
Board length compared
Same deck, four board lengths. Longer boards mean fewer end joints and more offcut risk.
| Board length | Deck boards to buy |
|---|---|
| 8 ft boards | 7 8 ft boards |
| 12 ft boards | 5 12 ft boards |
| 16 ft boards | 4 16 ft boards |
| 20 ft boards | 3 20 ft boards |
What else matters here
Eleven rows at 5 feet is 55 linear feet. Cut from 8 foot boards that is 7 boards and 3 feet of offcut per board, which is 21 feet of waste on a 55 foot job.
Ten foot boards are the answer nobody thinks of. A 10 foot board cuts into two 5 foot pieces with nothing left, so the same deck takes 6 boards and produces no offcut at all. Ten and fourteen foot decking is stocked by most yards and ignored by most buyers because 8, 12 and 16 are the lengths on the end of the aisle.
The general rule is worth carrying off this page: pick the stock length that divides by your run, not the one that is closest to it. A 5 foot run wants 10s, a 7 foot run wants 14s, a 9 foot run wants 18s if the yard has them.
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 5x5 deck?
Seven boards of 5/4 by 6 at 8 feet, or six at 10 feet, which cut into two 5 foot pieces each with no waste.
What length deck boards should I buy?
The stocked length that divides evenly by your run. A 5 foot run wants 10 foot boards, not 8 foot ones, even though 8s look like the closer fit.
How many joists for a 5x5 deck?
Five at 16 inches on center, including the two end joists.
The deck calculator takes any dimensions you like and hands back the same list.