Composite Decking Calculator
Composite deck boards and clips needed.
Enter your values
ⓘ Live results
Results
- Boards needed
- 45
- Board coverage each
- 7.33 sq ft
- Hidden fastener clips
- 540
- Face screws (if used)
- 540
Quick answer
Composite decking needs boards to cover the deck area plus waste, plus one clip per joist crossing per board.
boards = ceil(deck area x (1+waste%) / board coverage)
How to use the Composite Decking Calculator
- 1Enter the deck area and the composite board dimensions.
- 2Enter how many joists each board typically crosses.
- 3Add 10% waste for end cuts and picture-frame borders.
Worked example
Using the values the calculator loads with:
Inputs
- Deck area300 sq ft
- Board width5.5 in
- Board length16 ft
- Joists crossed per board6
- Waste allowance10 %
Results
- Boards needed45
- Board coverage each7.33 sq ft
- Hidden fastener clips540
- Face screws (if used)540
Frequently asked questions
Hidden clips or face screws?
Hidden fastener clips give a clean look; face screws are cheaper and easier for DIY.
Does this include the substructure?
No, use a separate joist and beam calculation — this only covers the decking boards and fasteners.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.