Decking Board Calculator
Enter your deck area, board dimensions and waste allowance to calculate how many decking boards you need.
Decking Board Calculator
Calculate the number of decking boards needed to cover a deck area, including a waste allowance.
This calculator provides a material estimate for general planning purposes only. Always add a safety margin and confirm quantities with your supplier or contractor before purchasing, since real-world waste, layout and offcuts vary by project.
This calculator divides your total deck area, inflated by a waste allowance, by the coverage of a single board to determine how many boards to purchase.
Example
- With the default values shown above, this calculator returns: Coverage per Board (sq ft) ≈ 5.50; Boards Needed ≈ 60.
Frequently Asked Questions
What is the formula?
Each board covers its width (in feet) times its length. Dividing your total deck area (plus waste allowance) by that coverage gives the number of boards needed, rounded up.
Does this account for gaps between boards?
Not directly — small gaps for drainage typically add only a few percent to material needs, which your waste allowance can absorb. For wide gaps, increase the waste percentage.