Deck Calculator
How many deck boards you need from the area, the board width, and a waste allowance.
How many deck boards you need. Boards run along the length; the width is divided by the board plus the gap.
Deck
Waste allowance
Boards to order
42
42 boards, each 4.8 m, including 10% waste. That is 201.6 m of decking.
- Across the width
- 38
- Each board
- 4.8 m
- Linear metres
- 201.6 m
- Joists, posts, and fixings are not included.
- Buy boards in the lengths the yard actually sells, then cut to the run.
Boards42
Measurements stay in this browser. Nothing is uploaded.
Worked example
A deck 4.8 m by 3.6 m, with 90 mm boards and a 5 mm gap, needs 38 boards across the width. With 10% waste that’s 42 boards, each 4.8 m — about 202 m of decking.
FAQ
- Which way do the boards run?
- Along the length you enter. The width is divided by the board width plus the gap.
- Should I add waste?
- Yes if you expect cuts around posts. 10% is the default; set it to none if you don’t want it.
- Are joists included?
- No. This is the decking boards only.