Deck Boards Needed Calculator
A deck is covered one row at a time. Work out how many rows fit across the width, multiply by the length, and you have the linear feet to buy.
Boards needed
29
- Deck area
- 192
- Rows of boards
- 26
- Linear feet with waste
- 457.6
- Area covered by one board
- 7.5
- Boards before waste
- 26
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
rows = ceil(12 x deck width / (board width + gap)), boards = ceil(rows x deck length x (1 + waste) / board length)
- rows
- The number of boards running across the deck width
- gap
- The spacing left between boards for drainage
- deck length
- The run the boards are laid along
- waste
- Extra allowance for cuts, defects and diagonal layouts
How to check the result by hand
- 1
Add the gap to the board width
A 5.5 inch board with a one eighth inch gap occupies 5.625 inches. Skipping the gap understates the deck by about half a board over a twelve foot width.
- 2
Divide the deck width in inches
Twelve feet is 144 inches, and 144 divided by 5.625 is 25.6, which rounds up to 26 rows of decking.
- 3
Multiply by the deck length for linear feet
Twenty six rows across a 16 foot deck is 416 linear feet, and ten percent for cuts takes that to 457.6 feet of board.
- 4
Convert to the lengths you buy
457.6 feet divided by 16 foot boards is 28.6, so 29 boards go on the order. Before waste the deck needs 26, which matches the row count.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Deck Boards Needed page.