Free Deck Board Calculator
Calculate how many deck boards you need based on deck dimensions, board width, and spacing. Includes waste for cuts.
A 2×6 is actually 5.5 inches wide
Typically 1/8 inch for wood
Boards Needed
29
Boards Needed vs Deck Length
How to Calculate Deck Boards
Formula
Boards Across = Deck Width / (Board Width + Gap)
Total Boards = Boards Across × Deck Length / Board Length × (1 + Waste)
A nominal 2×6 deck board is actually 5.5 inches wide. Include a 1/8-inch gap between boards for drainage and expansion. Board lengths come in 8, 10, 12, 14, 16, and 20 ft.
Example Calculation
A 16 ft by 12 ft deck with 5.5-inch (2×6) boards, 1/8-inch gaps, 16 ft board length, 10% waste.
- 01Board coverage width = (5.5 + 0.125) / 12 = 0.469 ft
- 02Boards across = 12 / 0.469 = 25.6 → 26 boards
- 03Linear feet = 26 × 16 = 416 lin ft
- 04Boards at 16 ft = 416 / 16 = 26 boards
- 05With 10% waste = 26 × 1.10 = 28.6 → 29 boards
Frequently Asked Questions
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