Deck cost per square foot
Estimates from this calculator's default prices for a deck up to about 4 ft off the ground with 36 ft of railing and 5 stair steps. Your local prices will differ, so change the defaults above to match quotes or supplier prices near you.
| Deck size | Pressure-treated | Per sq ft | Composite | Per sq ft |
|---|---|---|---|---|
| 10×10 (100 sq ft) | $3,950–$5,900 | $40–$59 | $5,950–$8,900 | $60–$89 |
| 12×12 (144 sq ft) | $5,000–$7,500 | $35–$52 | $7,350–$11,000 | $51–$76 |
| 12×16 (192 sq ft) | $6,150–$9,200 | $32–$48 | $8,850–$13,300 | $46–$69 |
| 14×20 (280 sq ft) | $8,250–$12,400 | $29–$44 | $11,650–$17,450 | $42–$62 |
| 16×20 (320 sq ft) | $9,200–$13,850 | $29–$43 | $12,900–$19,350 | $40–$60 |
Small decks cost more per square foot because the railing, stairs and setup don't shrink with the deck. Across these sizes, pressure-treated runs $29–$59 per sq ft and composite $40–$89.
How much does it cost to build a deck?
A 12×16 ft pressure-treated deck, up to 4 ft high, with 36 ft of railing and 5 steps comes to about $6,150–$9,200 installed here. Materials are about $2,130 of that. Labor is the biggest part: about 85 worker hours. The same deck in cedar is about $7,200–$10,800.
Composite deck cost
Composite decking, such as Trex, costs more than twice as much as pressure-treated boards: about $9.50 per sq ft for boards and hidden clips here, against $4 for treated boards and screws. Composite railing is about $45 per foot against $15 for wood. A 12×16 composite deck runs about $8,850–$13,300 installed with these defaults, and a 20×20 composite deck about $15,450–$23,150.
How much does a 14x20 deck cost?
A 14×20 ft deck is 280 sq ft. With these defaults it costs about $8,250–$12,400 in pressure-treated wood and $11,650–$17,450 in composite. In the composite version, the decking is about $2,660 and the railing about $1,620 of the materials.
12x12 deck cost
A 12×12 pressure-treated deck up to 4 ft high comes to about $5,000–$7,500. Built at ground level with no railing and a single step, it drops to about $3,200–$4,850, or $4,350–$6,500 in composite. Many codes require a guard once the deck is more than 30 in above grade, so check before you leave it off.
Replacing a deck
Tearing out and hauling away an old deck adds about $5 per sq ft by default. A 14×20 composite deck that replaces an old one comes to about $12,750–$19,150. Choose "Remove an old deck" above to include it.
What changes the price
- Height: a deck higher than 4 ft needs longer posts, bigger footings, bracing and more stairs. A 14×20 treated deck at second-story height with 14 steps comes to about $11,450–$17,150 here.
- Railing and stairs: each foot of railing and each step adds material and labor. On small decks they can be a third of the price.
- Permit and inspections: most towns require a permit for attached or raised decks. Enter your town's fee above.
How this estimate works
Framing materials are $3.50 per sq ft: our deck calculator's counts for a 16×12 deck (2×10 joists 16 in on center, ledger, rim, one doubled beam, 6×6 posts every 8 ft, four bags of concrete per footing, hangers) at its default prices come to about $3 per sq ft, plus about 15% for flashing, lag screws, post bases and connectors. Decking with fasteners is $4 per sq ft for pressure-treated 5/4×6 boards, $9.50 for composite with hidden clips, and $7.50 for cedar, which we assume at about twice the price of treated boards. Railing is $15, $25 or $45 per foot and stairs $30, $45 or $70 per step for wood, cedar or composite. Framing costs 20% less at ground level and 40% more above 4 ft. The contractor's markup on materials is 20%. Labor is 0.35 worker hours per sq ft (0.4 for composite), 10% less at ground level and 40% more above 4 ft, plus 0.3 hours per foot of railing and 1.5 hours per step, billed at $60 an hour including the contractor's overhead and profit. The range is the result minus 20% to plus 20%. Change any of these above. Fixr lists $15–$55 per sq ft for building a deck, and $15–$25 for pressure-treated wood (updated January 2023). Our default 12×16 treated deck, with railing and stairs, comes to about $40 per sq ft at the middle of its range: inside Fixr's overall range, above its pressure-treated figure.
Getting quotes
Get at least three quotes for the same size, height, decking, railing and stairs. Ask what size footings and joists they plan, whether the permit is included, and who hauls away the old deck. If a quote is far below this estimate, ask what's left out.
Questions
How much does a deck cost per square foot?
With this estimator's typical defaults, a pressure-treated deck up to 4 ft high costs about $29–$59 per sq ft installed and composite about $40–$89, depending on size. Smaller decks cost more per square foot. Change the defaults to match your area.
How much does a 14x20 deck cost?
About $8,250–$12,400 in pressure-treated wood and $11,650–$17,450 in composite with these defaults, including 36 ft of railing and 5 steps.
Is it cheaper to build a deck yourself?
Usually, by a lot. Labor is the largest part of a deck's price. A 12×16 pressure-treated deck needs about $2,130 of materials in this estimate, against $6,150–$9,200 installed. You still need a permit in most towns, and footings and framing have to meet local code.
How much does a composite deck cost?
A 12×16 composite deck, such as Trex, comes to about $8,850–$13,300 installed with these defaults, and a 20×20 composite deck about $15,450–$23,150.