Decking calculator
Enter the deck length, deck width, board width and gap for the boards across, the lineal metres to buy and the order with 10% extra. It uses the same formula as Decking in the MeisterCalc app.
Sources: WoodSolutions Technical Design Guide 21 (PDF).
Decking calculator
This calculator needs JavaScript, which is turned off or didn't load. You can still do it by hand: the formula and the worked example below give the same answers.
Boards across, lineal metres and the order with 10% extra. The same maths as Decking in the MeisterCalc app.
Published · By Sai Nath
Worked example: a 6 m × 4 m deck
Deck length 6000 mm (the way the boards run), deck width 4000 mm, boards 90 mm wide, 5 mm gap.
- Area: 6 × 4 = 24 m².
- Boards across: 4000 ÷ (90 + 5) = 42.1, rounded up to 43.
- Lineal metres: 43 × 6 = 258 m.
- Order: 258 × 1.10 = 283.8 m.
How it works
- Boards across = deck width ÷ (board width + gap), rounded up to a whole board.
- Lineal metres = boards across × deck length ÷ 1000.
- Order = lineal metres × 1.10, the same 10% the app adds for offcuts and mistakes.
The last board is counted whole even when only a sliver of it fits, which is safe for ordering. The calculator doesn't size joists, count screws or plan picture-frame borders.
Decking in MeisterCalc
Questions
How many lineal metres of decking are in a square metre?
1000 ÷ (board width + gap, in mm): 10.53 m per m² for 90 mm boards with 5 mm gaps. A real deck needs a little more, because the last board rounds up.
What gap should I leave between decking boards?
Use the figure in the board maker's installation guide. For timber decks in Australia, WoodSolutions recommends 2 to 5 mm at installation, depending on the timber and how dry it is.
Why does it add 10%?
The order line is the lineal metres plus 10% for offcuts and mistakes, the same allowance the app uses.
Sources
Building rules are set by the National Construction Code, the NZ Building Code or the Approved Documents and by your council, not by this page or the app.