Decking Calculator
Calculates deck surface board quantities across standard lengths (12 ft, 16 ft, 20 ft), pattern orientations (perpendicular, diagonal 45°, picture-frame border), hidden fastener clips, and color-matched composite screws.
Formula
Total Linear Ft = (Deck Area ÷ 0.4583 ft) × (1 + Waste %); Boards = Ceil(Linear Ft ÷ Board Length)
1. Deck Area = Length × Width 2. Board Width in Feet = 5.5 in ÷ 12 = 0.4583 ft (with 1/8" gap = 0.4687 ft) 3. Total Linear Feet = (Deck Area ÷ 0.4687) × (1 + Waste %) 4. Number of Stock Boards = Ceil(Total Linear Feet ÷ Stock Board Length) 5. Fasteners = Total Linear Feet × 2.5 screws/clips per lin ft
Inputs
- Deck Length (Parallel to house)
- Deck Width (Projection out from house)
- Decking Material
- Stock Board Length
- Board Orientation
Worked example
Calculating 16-ft composite deck boards and hidden fasteners for a 320 sq ft backyard deck.
Outcome: Deck area is 320 sq ft. Requires 683 linear feet of decking (751 linear ft with 10% waste). Dividing by 16-ft stock boards gives 46.9 boards, rounding up to 48 full 16-foot composite boards. Fasteners: 2 boxes of hidden clips (900 clips total).
What is the advantage of using 20-foot deck boards?
Using 20-foot deck boards allows you to span decks up to 20 feet wide in a single continuous board without unsightly staggered butt-joints, resulting in a cleaner architectural appearance.