Fence Board Count
Free Fence Board Count calculator with clear step-by-step results.
About Fence Board Count
Board count depends on effective coverage, not nominal width. A feather-edge board overlapping its neighbour by 25 mm covers 25 mm less than it measures, while a gapped picket fence covers more, so the overlap and gap fields pull in opposite directions on the same calculation.
Formulas
Effective coverage
Coverage mm = board width - overlap + gap
Boards required
Boards = ceil(fence length mm / effective coverage) x (1 + waste)
Worked example
With the default values below, Fence Board Count returns Boards to buy of 270. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Fence lengthminimum 0.1 m
- 30 m
- Board widthaccepts 20–400 mm
- 145 mm
- Gap between boardsaccepts 0–150 mm
- 0 mm
- Overlap for feather-edge boardsaccepts 0–120 mm
- 25 mm
- Waste allowanceaccepts 0–40 %
- 8 %
Results
- Boards to buy
- 270 boards
- Boards needed with no waste
- 250 boards
- Coverage per board after overlap
- 0.1200 m
- Overlap as a share of board width
- 17.2% %
Step by step
- 1Values used
- 2Effective coverage
- 3Boards required
- 4Boards to buy= 270 boards
- 5Boards needed with no waste= 250 boards
- 6Coverage per board after overlap= 0.1200 m
- 7Overlap as a share of board width= 17.2 %
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How much overlap does feather-edge need?
At least 20-25 mm so the boards stay lapped as timber shrinks. Less than that and gaps open up in the first dry summer.
Should picket fences have gaps?
Yes - a gap roughly equal to the picket width is traditional and lets wind through, which greatly reduces the load on the posts.