Deck Calculator
Enter your dimensions for an instant answer — the exact quantity to buy (waste included), a material cost, and an estimated installed cost. Change any figure to update the result live.
| ITEM | QTY | PRICE RANGE |
|---|---|---|
| linear ft | 461 | $806.75–$2,766 |
| Estimated material total | $806.75–$2,766 |
- 16 ft boards: ≈ 29 boards
How much decking do I need?
Enter the deck length, width and board width — 5.5 inches for standard 5/4×6 wood or composite boards, including Trex-style products. The calculator converts the surface area to linear feet of decking, adds 10% for cuts and pattern waste, and shows how many 16-foot boards to buy.
The estimate covers the walking surface. Framing — joists, beams, footings and fasteners — is separate; as a rule of thumb, joists on 16-inch centers add roughly one linear foot of joist per square foot of deck.
Formula & methodology
linear ft = deck ft² ÷ (board width in ÷ 12), + 10% waste
Surface area divided by the width one board covers, with a 10% allowance. Wood decking sits at the low end of the $1.75–$6 per linear foot range; composite at the top.
All constants are published on the material reference; the full model is on the methodology page.
16 ft × 12 ft deck: you need 419 linear ft (buy 461 with waste), about $806.75–$2,766 in materials. See how we calculate this →
Popular sizes
Deck cost
Per our model an installed deck runs about $21–$37 per square foot at the US average — labor dominates, and composite boards push materials to the top of the range.
deck cost by state →Frequently asked questions
How much decking do I need?
Divide the deck area by the width one board covers (5.5 in ≈ 0.46 ft) to get linear feet, then add 10% for cuts. A 16×12 ft deck needs about 461 linear feet, or roughly 29 sixteen-foot boards.
How many deck boards do I need?
Divide the deck area by the coverage of one board (board width in feet × length), then add ~10% for waste. The calculator returns linear feet and board counts.
How much does a deck cost to build?
Per our model, about $21–$37 per square foot installed at the US average — a 16×12 deck lands around $4,100–$7,200 depending on board choice. See the deck cost-by-state page for a local estimate.
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