Deck board calculator
Estimate board counts with complete edge coverage or solve a uniform gap from your chosen board count and two edge allowances.
Deck board calculator
With no exterior gaps: coverage = N*b + (N−1)*g. Therefore the minimum coverage count is ceil((W+g)/(b+g)); along the length rows = ceil(L/boardLength). Waste affects purchased count only.
Geometric estimate only. Product dimensions, spacing and accessories are supplied by you; no installation or structural certification.
Results
A QUICK WALKTHROUGH
How to use this tool
- Select count or spacing mode and a common length unit.
- Enter the required dimensions and user allowances.
- Review exact counts, full coverage, final trim, gap and comparison rows.
Model
With no exterior gaps: coverage = N*b + (N−1)*g. Therefore the minimum coverage count is ceil((W+g)/(b+g)); along the length rows = ceil(L/boardLength). Waste affects purchased count only.
Model
For spacing: g=(W−left−right−N*b)/(N−1). N=1 has no interior gap: matching available span is nonunique; otherwise it cannot meet both edges. Negative g is infeasible. A zero final trimmed width indicates the last position adds only its preceding gap; this geometric model is not a cutting plan.
Report
Yes. Copy and TXT contain the complete frozen inputs, formulas, exact quantities and all rows.
GOOD TO KNOW
Common questions
Why add the gap in the numerator?
N boards have N−1 gaps, not N gaps. For W=220, b=100, g=10, two boards cover only 210; three are needed. No exterior gap is counted.
Can I export the results?
Yes. Copy and TXT contain the complete frozen inputs, formulas, exact quantities and all rows.
How is it calculated?
With no exterior gaps: coverage = N*b + (N−1)*g. Therefore the minimum coverage count is ceil((W+g)/(b+g)); along the length rows = ceil(L/boardLength). Waste affects purchased count only.