Need to know how many deck boards to buy? Enter the deck size and the board you picked. You get the number of boards, the rows and the total board length, with extra for cuts included.
Your shopping list
39Deck boards to buy
26Rows of boards
192 sq ftDeck area
- Board length in total457.6 ft
A 1/8 in gap is left between boards. Diagonal boards use about 15% more. Extra of 10% is included.
How to use the Decking Board Calculator
- Enter the deck length and width.
- Pick the board width and the board length sold at your store.
- Choose straight or diagonal boards and read the number to buy.
The math behind it
Rows = deck width x 12 / (board width + 1/8 in), rounded up
Boards = rows x deck length / board length, rounded up
Diagonal boards add about 15% more
A worked example
What we typed in
- Deck length: 20 ft
- Deck width: 14 ft
- Board width: 5.5 in wide (5/4 x 6 or 2×6)
- Board length: 12 ft
- Board layout: Diagonal (45 degrees to the joists)
- Extra for mistakes and cuts: 10%
What we got
- Deck boards to buy: 64
- Rows of boards: 30
- Deck area: 280 sq ft
- Board length in total: 759 ft
Tips from the job site
- Pick a board length close to the deck length to cut waste.
- Boards laid at 45 degrees need joists about 12 in apart.
Common questions
How many deck boards do I need for a 12 x 16 deck?
A 12 x 16 ft deck with 5.5 in wide boards has 26 rows. With 16 ft boards and 10% extra you buy about 29 boards.
How much extra should I buy?
10% is enough for straight boards. Buy more for diagonal layouts or if the boards have defects.
See all Deck Calculators.