Decking Calculator
Calculate the number of decking boards, joists, screws and fixings needed for your garden deck.
How to use this calculator
1. Measure your deck area
Measure the length and width of your planned deck in metres.
2. Choose board direction
Decide if boards will run lengthwise or widthwise - this affects the joist layout.
3. Select joist spacing
Choose 400mm centres (standard) or 450mm for lighter-use decks.
4. Select materials
Choose your decking board length and joist size based on span requirements.
5. Calculate materials
Click Calculate to see the exact quantities of boards, joists, screws and fixings needed.
6. Add to project
Save the materials to a project to compare prices from UK suppliers.