Deck Cost Calculator
Estimate a new deck. Enter the size and material, then add railing, stairs, and demolition, and choose DIY or contractor to see a cost range and per-square-foot price.
Example: with Deck length 16 ft · Deck width 12 ft · Decking material Composite ($45/sq ft) · Railing length 28 ft → Estimated cost: $10,560.
- Low estimate$9,504
- High estimate$12,144
- Cost per sq ft$55/sq ft
Computed by the calculator below using its default values. Change any input to see your own numbers.
3D deck · drag to rotate
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Decking material sets the baseline, but railing and stairs add up fast — roughly $60 per linear foot of railing and per stair step. Removing an old deck adds demolition cost. Choosing DIY drops the labor portion (the calculator applies a materials-only factor), though it trades money for time and skill. The figures are installed estimates; height, footings, and permits can push the final number higher.
Average deck size & what people build
The average new deck runs 300–400 sq ft (about 19 × 19 ft); the most-built sizes are 12×16, 12×20, 15×20, 14×24 and 20×24, and small platforms start around 10×10. This page’s 16 × 12 ft default (192 sq ft) is a common starter size. On materials, wood still carries the majority of decking volume — pressure-treated lumber is roughly 40% of the wood segment — but wood-plastic composite has climbed to about 28% of U.S. decking demand and keeps gaining as boards outlast the 10–15-year repaint-and-replace cycle of treated lumber.
Size: TimberTech deck-size guide (2023); Trex deck-size resources. Material mix: Mordor Intelligence wooden-decking market report (2025–26); Trex Co. FY2024 10-K.
How it’s calculated
Cost = area × $/sq ft + railing × $/ft + stairs × $/step (× DIY factor) + demolition; a low–high range is shown.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Pricing the boards but forgetting railing, stairs, and demolition.
- Comparing DIY to contractor prices without the labor difference.
Frequently asked questions
Does material include labor?
The per-square-foot rates are installed (material + labor). The DIY option strips out most labor to approximate a materials-only build.
Why are railing and stairs separate?
They're labor-intensive and priced per foot and per step, so breaking them out makes the estimate more accurate.
What can raise the price further?
Elevated decks, complex footings, permits, and add-ons like lighting or built-in seating all add cost.