Deck Board Spacing Calculator
Plan deck-board courses, target gaps, edge-board rip width, full-board quantity, linear length and material cost.
Default project preview
26 courses
Edge-board width
4.44 in
Target gap
0.125 in
Boards per course
1
Purchase boards
29
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Courses = round up ((deck width + gap) ÷ (board face width + gap)). Excess coverage is divided between both edge boards. Purchase boards include stock-length cuts and waste.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Deck Board Spacing Calculator questions
Why rip both edge boards?+
Splitting the adjustment can create a more balanced layout than leaving one very narrow final board.
Should wet pressure-treated boards use the same gap?+
Fresh lumber may shrink as it dries. Follow the decking manufacturer or supplier guidance for installed spacing.
Does this calculate joists?+
No. Use the decking calculator for joist and fastener quantities.