Deck Square Footage Calculator
Enter your deck dimensions and board profile to get exact square footage, board count, linear feet, and deck screw quantity — designed for pressure-treated, cedar, or composite decking.
Pick the longest board that fits the deck length to minimize joints.
10% standard for rectangular decks; 15% for picture-frame or diagonal layouts.
Results
Assumes 16-inch on-center joist spacing and a 1/8-inch gap between boards. For hidden-fastener systems or diagonal decking, increase waste to 15%.
Deck Board Math
Deck boards run perpendicular to the joists, spanning the shorter dimension of the deck. The math is straightforward but watch for two common mistakes:
- Nominal vs actual width:a "1 × 6" or "5/4 × 6" board is 5.5 inches wide, not 6 inches. A "2 × 4" is 3.5 inches, not 4. Always use actual dimensions in calculations.
- Gap between boards: add a 1/8-inch gap between boards for drainage and expansion. Over a 12-ft deck width, this adds about half a board, so include it in the math.
Boards per row = ⌈ Deck Length ÷ Board Length ⌉
Total boards = Rows × Boards per Row × (1 + waste)
Decking Material Comparison (2026)
Pressure-Treated Pine
$2–4 per linear ft. Most economical. Service life 15–20 years with annual sealing. Available everywhere.
Western Red Cedar
$4–8 per linear ft. Naturally rot-resistant, beautiful aging. Lasts 15–25 years. Requires annual maintenance.
Composite (Trex, TimberTech)
$5–12 per linear ft. Wood-plastic blend. 25–30 year warranty. No staining, just occasional washing.
PVC / Capped Composite
$8–15 per linear ft. Highest durability, slip-resistant texture, 50-year warranty. Premium price.
Frequently Asked Questions
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Sources
The figures on this page are based on data from these authoritative industry sources.
- The Home Depot Buyer’s Guides — Retail price ranges for flooring, paint, and finishing materials.