Decking Calculator
Calculate deck boards, joists, and hardware needed for your deck project.
Decking Calculator
Calculate materials needed for your deck project
Formula
Boards = (Width ÷ Board Width) × (Length ÷ Board Length)Includes 10% waste factor
How to Use This Calculator
- 1
Enter deck size
Enter the length and width of your deck.
- 2
Set board specs
Enter board width, length, and gap between boards.
- 3
Set joist spacing
Choose joist spacing (16" is standard for most decking).
Frequently Asked Questions
What is standard joist spacing for decking?
16 inches on center is standard. Use 12 inches for diagonal patterns or composite decking.
How much gap between deck boards?
Leave 1/8" to 1/4" gap for drainage and expansion. Composite may need more.
How much extra decking should I buy?
Plan for 10-15% extra for cuts, waste, and future repairs.