Deck Board Calculator
Size your decking order. Enter the deck dimensions, board width, and gap to get the number of board rows, total linear feet to purchase including waste, and an estimated cost.
Updated June 2026 · Free · No sign-up
Your project
Estimate
Decking to buy · Includes waste allowance
- Board rows
- 35rows
- Estimated material cost
- $1,270.50
Estimates are guidance only and exclude tax, labor, and site conditions unless stated. Confirm with a local pro.
How it's calculated
No black boxes — here is the exact math behind your estimate, so you can check it or adapt it for your own quote.
- 1
Coverage per row (ft) = (board width + gap) ÷ 12 - 2
Rows = ⌈ deck length ÷ coverage per row ⌉ - 3
Linear feet = rows × deck width × (1 + waste% ÷ 100) - 4
Cost = linear feet × price per linear foot
Worked example
A 16 ft × 12 ft deck using 5.5" boards with a 1/8" gap and 10% waste.
Inputs
- Deck length
- 16 ft
- Deck width
- 12 ft
- Board width
- 5.5 in
- Gap between boards
- 0.125 in
- Waste allowance
- 10 %
- Price per linear foot
- 2.75 $/ft
Result
- Decking to buy
- 463 lin ft
- Board rows
- 35 rows
- Estimated material cost
- $1,270.50
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Deck Boards cost by state
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