Deck Board Spacing Calculator
Calculate even deck board layout and adjusted gap size to fill a fixed width.
Estimate only — not a substitute for a licensed tradesperson, a certified engineer, or sign-off from your local building surveyor. Verify against current standards and site conditions before ordering materials or starting work.
Result
- Number of boards
- 44
- Adjusted gap to fit evenly
- 5.02mm
With only one board there are no gaps to share out, so the adjusted gap shows 0. If the boards cannot fit the width, the gap is shown as 0 rather than a negative number - reduce the board width or increase the total width.
What this is based on
Arithmetic - board and gap layout across a deck width. Gap size is a drainage/movement preference set by the decking manufacturer, not a code limit.
We cite the clause and link to the publisher so you can read the source yourself. We do not reproduce the text or tables of the NCC or of any Australian Standard.