Cost calculator
Deck cost estimator: what your deck will cost to build
Deck size, material, railing and stairs in — a line-by-line cost estimate out, with the DIY saving shown against the installed price.
Your project
The dimension the deck boards run along — usually the side parallel to the house.
Joists run this way, so this is the number that has to fit the joist span table.
Material changes price and maintenance, not board count — every option here is a 5.5 inch face.
Over 30 inches means guard rail and, on most decks, a flight of stairs.
Metro labour markets run 15-30% above the national average; rural areas run below it.
Estimated installed cost
$10,263
192 sq ft · $53 per sq ft
- Decking material
- $841
- Framing lumber and hardware
- $2,112
- Footings (3)
- $480
- Railing (56 lin ft)
- $2,240
- Stairs
- $750
- Labour
- $3,840
- Cost per square foot
- $53.46
- Same deck built DIY
- $6,423
- You would save building it yourself
- $3,840
Planning figures, not a quote. Permits, difficult access, rock in the footing holes, a second-storey deck or a curved edge each move the real number by 10 to 30 percent. Get three written bids before committing.
The shareable link reopens this calculator with your exact inputs.
What a deck costs per square foot
Installed, a pressure-treated deck runs about $25 to $35 per square foot, cedar $30 to $45, composite $35 to $55, and PVC or ipe $45 to $70. Those numbers already contain the framing, footings and labour, which is why they look so much higher than the price of the boards.
Material is roughly a quarter of an installed deck, framing and hardware another quarter, and labour close to half. That split is why DIY saves so much on a deck and so little on, say, a concrete driveway where the material dominates.
Size works in your favour. The footings, the ledger detail, the permit and the crew mobilisation cost nearly the same on a 200 square foot deck as on a 400 square foot one, so the cost per square foot drops as the deck grows.
The lines people forget to budget
Railing. At $40 per linear foot in pressure-treated and $200 in glass, the rail on a three-sided deck routinely costs more than the decking. Decide the rail before you fall in love with a board.
Stairs. A flight of five steps down to grade is $450 to $1,250 installed, including the landing pad, stringers, treads and its own rail. Stairs are the most labour-dense part of a deck per square foot.
Permits and inspections, $150 to $700 depending on the jurisdiction. Skipping the permit saves that and costs far more at resale, when the deck shows up as unpermitted work on the inspection report.
Where the real savings are
Choosing pressure-treated framing under composite decking is the standard value play: the expensive board is the one you touch, and nobody sees the joists. Composite framing exists but roughly doubles the framing line.
Keeping the deck under 30 inches above grade eliminates the guard rail requirement in most codes, which on a mid-sized deck is a four-figure saving before it is a design choice.
Building in autumn or winter gets better pricing from crews whose spring is already booked. Lumber prices also tend to sit below their spring peak.
Deck cost by size and material
Installed, including framing, footings and labour. Railing and stairs extra.
| Deck size | Pressure-treated | Cedar | Composite | PVC |
|---|---|---|---|---|
| 10 × 10 ft (100 sq ft) | $2,700 | $3,300 | $4,200 | $5,000 |
| 12 × 12 ft (144 sq ft) | $3,888 | $4,752 | $6,048 | $7,200 |
| 12 × 16 ft (192 sq ft) | $5,184 | $6,336 | $8,064 | $9,600 |
| 16 × 20 ft (320 sq ft) | $8,640 | $10,560 | $13,440 | $16,000 |
| 20 × 24 ft (480 sq ft) | $12,960 | $15,840 | $20,160 | $24,000 |
Deck cost line items
Typical installed ranges, national average.
| Line item | Low | Typical | High | Unit |
|---|---|---|---|---|
| Decking and framing | $25 | $40 | $65 | per sq ft |
| Framing lumber alone | $7 | $11 | $16 | per sq ft |
| Labour | $12 | $20 | $32 | per sq ft |
| Railing | $40 | $80 | $150 | per lin ft |
| Stairs | $90 | $150 | $250 | per step |
| Footings | $90 | $160 | $300 | each |
Frequently asked questions
+How much does it cost to build a deck?
Nationally, $25 to $65 per square foot installed depending on material. A 12 by 16 foot pressure-treated deck runs about $5,000 to $7,000; the same deck in composite is $8,000 to $11,000 before railing.
+How much does a 20x20 deck cost?
400 square feet installed is roughly $10,000 to $14,000 in pressure-treated, $16,000 to $22,000 in composite, plus $3,000 to $8,000 of railing depending on the style you pick.
+Is composite decking worth the extra cost?
Over 25 years, usually yes. Composite costs 30 to 50 percent more upfront and eliminates the sanding, staining and board replacement that a wood deck needs every two to three years. Under about ten years of ownership, pressure-treated wins on money.
+How much can I save building a deck myself?
About half. Labour is roughly 50 percent of an installed deck, so a $12,000 contract is around $6,000 in materials. Budget several weekends, a concrete day and the cost of the permit and inspections, which you still need.
+Does a deck add value to a house?
Industry cost-versus-value studies consistently put a wood deck addition near the top of the list, recovering roughly 50 to 65 percent of its cost at resale — higher than most kitchen or bathroom work.
+What is the cheapest way to build a deck?
Pressure-treated everything, a ground-level platform under 30 inches so no guard rail is required, a simple rectangle with no bump-outs, and boards ordered in a length that matches the deck exactly.