Deck Cost Calculator
A deck costs about $36 a square foot in pressure-treated pine, which for a 20 by 20 in Atlanta is $14,455. The number missing from every other estimate is the height: the same deck at eight feet is $17,700 and at ground level without a guard it is $9,888. A deck is a structure, not a surface, and 41% of the money is in footings and framing you will never see again.
Estimate the cost for your home
Estimated cost of the finished deck
$15,390
typical · range $11,394 to $19,386 · 400 sq ft at 3 ft high · $38 per sq ft · 8 footings
Labour priced at national wages. Enter a ZIP code to price it for your area. 61% of this figure comes from modelled material prices — each line shows its own uncertainty.
Priced from bls.gov Aug 2026epa.gov Aug 2026how every line is sourced
The one input that changes the answer for you.
The default, and much the cheapest board there is. It moves, it splits at the fastener heads and it needs sealing every couple of years, and it will still be there in twenty if somebody does that.
Posts, rails and balusters in timber. Cheapest, and it is the part of a wood deck that needs sealing most, because it takes the weather from every side.
1 / 4
The figure above is already calculated. Each step just makes it more yours, and you can stop at any of them.
A deck is not a surface, it is a structure
Which is why the height above ground changes the price as much as the footprint does.
- Footings, framing and posts
- 41%
- Boards, railing, stairs and finish
- 59%
41% of this figure is 8 concrete footings and the framing above them — the parts nobody looks at once the boards are down, and the only parts that decide whether the deck is safe. At 3 feet it is also above the height where a guard is normally required, so the railing is not a style choice. A quote that is light on framing and generous on boards is telling you where its money went.
Wood or composite, over ten years
Timber costs less to build and has to be sealed every couple of years. This is the same deck, both ways, with that arithmetic done.
| Board | To build | Sealing | At ten years |
|---|---|---|---|
| Pressure-treated pine | $15,390 | +$3,542 | $18,932 |
| Western red cedar or redwood | $17,030 | +$3,542 | $20,572 |
| Wood-plastic composite | $18,139 | none | $18,139 |
| Cellular PVC | $19,859 | none | $19,859 |
| Tropical hardwood (ipe and similar) | $20,546 | +$3,542 | $24,088 |
The cheapest to build is not the cheapest at ten years. On this deck wood-plastic composite ends up lowest at $18,139, because sealing a timber deck every couple of years catches up with the price of a board that never needs it. Whether that changes your mind is a separate question — timber feels different underfoot and composite gets hot in the sun — but the money should be on the table when you decide.
Or a patio on the same footprint
A paver patio of 400 square feet comes to $8,806 from our own model, against $15,390 for this deck — 175%. The gap is not finish, it is engineering: a patio sits on the ground and a deck is held above it by footings, framing and posts. Where a deck earns the difference is level ground it does not have: on a slope, or off a door that is three feet above the garden, a patio needs retaining and steps and the two prices converge fast.
| Line item | Qty | Cost | Source |
|---|---|---|---|
| Permit and inspection1 where a permit is pulled | 1permit | $180–$720 | estimated±60% |
| Footings: tube, concrete and post baseposts at ~8 ft centres, minimum four | 8footing | $384–$1,040 | estimated±46% |
| Dig, set and pour the footings2 hours per footing | 16hour | $704–$756 | sourced |
| Ledger, beams, joists, hangers and postsarea, increased 4.5% per foot of height for longer posts and bracing | 454sq ft | $1,725–$3,904 | estimated±39% |
| Carpenter: frame the deck6 h + 0.065 h per sq ft, increased 5% per foot of height | 35.9hour | $2,030–$2,181 | sourced |
| Pressure-treated pine decking boardsdeck area where the board is pressure-treated | 400sq ft | $1,080–$2,320 | estimated±36% |
| Lay and fasten the deckingarea × hours per sq ft for the chosen board | 20hour | $1,131–$1,215 | sourced |
| Wood railing, suppliedrailing length where the railing is wood | 60linear ft | $1,440–$3,120 | estimated±37% |
| Fit the railingrailing length × hours per linear foot | 18hour | $1,018–$1,093 | sourced |
| Stair stringers, treads and railone per riser | 5riser | $450–$1,200 | estimated±45% |
| Build the stairs2 h per riser + 3 h where there are stairs | 13hour | $735–$790 | sourced |
| Seal or stain the timberdeck area × 1.35 for the railing, where the timber is sealed | 540sq ft | $297–$810 | estimated±46% |
| Site protection and clean-up3 h + 1 h per 4 footings | 5hour | $220–$236 | sourced |
| Total | $11,394–$19,386 | ±26% |
Where these numbers come from
- The ten-year arithmetic, which changes the ranking
- Pressure-treated pine is the cheapest deck to build at $14,455 and needs sealing about every two years. Composite costs $17,135 and needs nothing. Add the sealing and at ten years the order reverses: $17,997 against $17,135, with wood-plastic composite lowest of all at $17,135. This is maintenance of the product rather than any kind of financial advice, and the resealing figure is our estimate — it costs more than the first coat because the deck has to be washed and lightly sanded first.
- If your deck is older than 2004
- EPA, Chromated arsenicals (CCA) states that “in December 2003, chromated arsenicals manufacturers voluntarily discontinued manufacturing chromated arsenicals-treated wood products for homeowner uses”, and that before 2004 that wood “was used in residential structures such as decks and playsets”. So an older deck is likely built from timber treated with an arsenic compound. It does not make the deck dangerous to stand on, and it does mean the wood should not be burned and should not be dry-sanded, and that it goes to landfill rather than to a wood recycler. EPA also notes that a penetrating coating applied regularly may reduce leaching from wood already in place. Modern treatments, covered in EPA, Overview of wood preservative chemicals, are copper-based instead. Both retrieved 2026-08-23.
- The two items that cost almost nothing and matter most
- The ledger — the board bolted to the house that carries one whole side of the deck — and the flashing above it. A ledger fastened with the wrong screws, or one with no flashing to keep water out of the wall behind it, is how decks come away from houses and how the wall behind them rots invisibly. Neither is a line you will notice in a quote and both are worth asking about by name: what fasteners, and does the flashing go behind the cladding.
- Labour rates by area
- BLS Occupational Employment and Wage Statistics, May 2025, for carpenters and labourers, adjusted to your metropolitan area. Retrieved 2026-08-20. Benefit load from BLS Employer Costs for Employee Compensation. Carpenters are published for 526 of the 530 areas in our index, so this is one of the few pages here where the wage is almost always that trade’s own figure. The hours per square foot are our estimate.
- The one number a national model cannot give you
- Footing depth, which is set by the local frost line and runs from about a foot in the south to four feet or more in the north. The same deck genuinely costs more to found in Minnesota than in Georgia, and it is not a labour-rate difference — it is more hole, more tube and more concrete per footing. Your building department will tell you the number in one phone call, and it is the first thing a local contractor prices.
- Or build a patio instead
- A paver patio of the same 400 square feet comes to $8,309 from our own model against $14,455 here — a deck is 174% of it. The difference is engineering rather than finish. What a deck buys is level ground you do not have: off a door that is three feet up, or on a slope, a patio needs retaining walls and steps and the two converge quickly. A deck also lets rain reach the soil underneath, which a patio does not — USGS Water Science School, Runoff: Surface and Overland Water Runoff covers what that changes downhill. Retrieved 2026-08-22.
- Material prices
- Modelled estimates, not sourced prices. No public, machine-readable source of US residential material prices exists, and we would rather say so than pretend otherwise. Each line carries its own uncertainty band. How we estimate them.
Contractor overhead and profit applied at 33–43% over direct cost. Data last reviewed 2026-08-23.
What this figure does not include
- Anything the ground turns out to be
- Footings are priced for ordinary soil at a normal frost depth. Rock, fill, a high water table or a slope that needs stepped footings each change the excavation completely, and none of them shows until the first hole is open.
- Structural design and engineering
- Most jurisdictions accept a prescriptive deck built to a published span table. A deck above a certain height, one carrying a hot tub, or one cantilevered beyond what the tables allow needs an engineer, and that is a separate cost before anybody digs.
- Roofs, pergolas, screens and hot tubs
- Anything above the deck surface changes the structure below it. A hot tub in particular is several thousand pounds concentrated on a few square feet, and a deck framed for people will not carry one.
- Electrical and lighting
- Deck lighting, an outdoor outlet or a feed to a hot tub are electrical work under their own rules, and the cable has to be run before the boards go down. Deciding afterwards means lifting them.
- Landscaping underneath and around
- What happens under a raised deck — gravel, membrane, skirting, or nothing — and the planting around the edge are separate work. Water still reaches the ground through a deck, which is one real difference from a patio.
Questions people actually ask
How much would a 12x12 deck cost to build?
About $7,479 in Atlanta in pressure-treated pine with a wood railing and a short flight of steps, in a range of $5,401 to $9,557. That is $52 a square foot, which is noticeably dearer per foot than a large deck — a 20 by 20 comes to $36. The reason is that a deck is a structure rather than a surface: the footings, the ledger and the framing do not scale down with the area, and neither does the crew turning up. If you are choosing between 12 by 12 and something larger, the extra square feet are much cheaper than the first ones were.
How much should a 20x20 wood deck cost?
About $14,455 in Atlanta in pressure-treated pine with a wood railing and five steps, in a range of $10,492 to $18,417 — $36 a square foot. Before comparing that with a quote, check two things it assumes. The height: this is a deck three feet above the ground, and the same 400 square feet eight feet up is $17,700, because the posts are longer, the stairs are longer and the guard is not optional. And the railing: at ground level with no guard required, the same deck is $9,888. Height changes this price as much as area does, and almost no quote comparison accounts for it.
How much would a 14x20 deck cost?
About $11,521 in Atlanta in pressure-treated pine, or $12,378 at 16 by 20 — a difference of $858 for 40 more square feet, which works out at about $21 a foot against $41 for the deck as a whole. That gap is the single most useful thing on this page when you are still deciding the size: growing a deck is far cheaper per square foot than building one, because the footings, the ledger and the crew visit are already paid for.
What is the average cost to build a composite deck?
About $19,297 for a 20 by 20 in Atlanta with a composite railing — $48 a square foot against $36 for pressure-treated pine. So composite costs about 34% more to build, and here is the part nobody puts in the comparison: timber has to be sealed every couple of years and composite never does. Run this deck out ten years and pressure-treated comes to $17,997 against $17,135 for composite. The cheaper board to build is the dearer one to own, and the crossover happens well inside the life of either.
How much would a 20x20 composite deck cost?
$19,297 in Atlanta, built, with a matching composite railing and five steps. What you are buying for the premium over timber is the absence of a chore: no sanding, no stain, no Saturday every second spring. What you are giving up is that composite gets genuinely hot in direct sun in a way timber does not, and that a damaged board cannot be sanded out — it is replaced. Neither of those shows in a price, and both are worth knowing before the money decides it for you.
Taken from Google’s “people also ask” results for this search on 23 August 2026, not invented.
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- How we calculate
The formula, the sources, and an honest account of which parts of the model are weak.