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Deck Cost Calculator

This deck cost calculator turns your deck's length, width, and decking material into a whole-build price — framing, decking, railing, and stairs — as a low-to-high range, plus the board and joist counts you'd hand to a lumberyard.

Wood vs composite, liveRates editable · reviewed July 2026Cost model + materials takeoff
16 ft12 ft29 boards
Decking material
Height above grade
Regional cost level
Rates — editable ($/sqft, $/lf, $/step)reviewed July 2026

Rate edits are remembered for this session — material presets refill them when you switch decking.

BUILT COST192 SQFT
$5,290 – $8,836
$27.55–$46.02/sqft
structure (materials + labor)$3,840 – $6,336
railing (40 lf)$1,000 – $1,600
stairs (3)$450 – $900
deck boards (16 ft) · joists29 · 13
WOOD VS COMPOSITE, SAME DECK
Pressure-treated pine$5,290 – $8,836
Composite$7,442 – $12,372

Estimates only, not quotes. Prices are editable national averages — confirm current pricing and quantities with your supplier before you buy.

Plain-English tour

How this deck cost calculator works

This calculator runs two models side by side from the same measurements. The first is a materials takeoff: length × width gives deck area, which converts into a whole number of 16-ft decking boards (after a waste allowance for cuts) and a joist count spaced 16 inches on-center along the deck's length. The second is a cost model built from editable $/sq ft ranges for the decking-and-substructure package, plus separate per-linear-foot railing pricing and a per-step stair price — because railing and stairs don't scale with square footage the way decking does.

Switching height to "30 in and over" applies a 10% multiplier to the structure cost, reflecting the deeper or engineered footings and code-required guardrail that height typically triggers. Switching from Pro to DIY drops the $15–$25/sq ft labor line and instead adds an 8% allowance on top of materials for fasteners, joist hangers, and flashing tape — DIY here still assumes you're paying full retail for lumber.

Railing length defaults to 2×width + length, which assumes a deck attached to the house along its "length" side (no railing needed where it meets the house) — edit that field directly if you're building a freestanding or island deck that needs railing on all four sides.

Driving screws into composite deck boards over pressure-treated joists — a deck cost calculator prices framing and decking separately
Composite vs wood only moves the surface and railing lines — the frame prices the same.
Finished composite backyard deck with black metal railing — installed deck cost estimated by assembly
Framing, decking, railing, footings — an itemized deck budget beats one guessed number.
Show the math

The deck cost formula

structure (pro) = area × ($/sqft material + labor) × height mult
structure (DIY) = area × material × height × 1.08 fasteners
railing = lf × $/lf · stairs = steps × $/step
total = (structure + railing + stairs) × region
boards = ceil(area ÷ 7.33 × (1 + waste)) · joists = ceil(L×12 ÷ 16) + 1
With the defaults

Worked example: what a 12×16 deck costs

Default inputs: a 16 ft × 12 ft deck (192 sq ft) in pressure-treated pine, built by a pro, in a typical-cost region, under 30 in high, with 3 stair steps and 10% board waste.

  1. 1. Area16 × 12 = 192 sqft
  2. 2. Structure192 × ($5–$8 + $15–$25) × 1.0 = $3,840–$6,336
  3. 3. Railing40 lf (auto: 2×12 + 16) × $25–$40 = $1,000–$1,600
  4. 4. Stairs3 × $150–$300 = $450–$900
  5. 5. Total× 1.0 region = $5,290–$8,836 · $27.55–$46.02/sqft
  6. 6. Boardsceil((192 ÷ 7.33) × 1.10) = 29
  7. 7. Joistsceil((16 × 12) ÷ 16) + 1 = 13

Switch decking to composite at the same 16×12 footprint, same mode and region, and the total becomes $7,442–$12,372 ($38.76–$64.44 per sq ft) — composite's higher material rate and its pricier composite/metal railing band both push the total up, even though the board and joist counts don't change.

What we assume

Assumptions & defaults

Deck calculator assumptions
Decking waste10% default (0–25% editable)
Height multiplier×1.1 at 30 in+ above grade
DIY fastener allowance+8% of materials
Joist spacing16 in on-center
Board coverage16 ft × 5.5 in = 7.33 sqft
Materials $/sqftPine $5–8 · cedar $7–11 · composite $11–16 · PVC $13–19
Pro labor$15–$25 per sqft
Railing $/lfWood $25–40 · composite/metal $50–90
Stairs$150–$300 per step

All prices are editable national-average estimates, reviewed July 2026.

Where the numbers come from

Sources & standards

Joist spacing, footing-depth practice, and the guardrail-height trigger reflect the American Wood Council / Southern Pine Council's Prescriptive Residential Wood Deck Construction Guide (DCA 6) and the International Residential Code, Section R312 (Guards) and Section R403 (Footings) — always confirm the current locally-adopted code and frost depth with your building department before you build. Decking and railing ranges are cross-checked against composite and PVC decking manufacturer installation guides, which publish fastener spacing and material-coverage figures, alongside general contractor bid ranges for pressure-treated and cedar lumber. Prices reviewed July 2026 — see how our price reviews work.

Before you build

Frequently asked questions

Do I need a permit to build a deck?
Most jurisdictions require one once a deck exceeds a certain size or sits a certain height above grade — commonly the same 30-inch threshold this calculator uses for its height multiplier. A deck built low to the ground and attached to an existing door is sometimes exempt. Check with your local building department before digging <a href="/concrete-calculator/">footings</a>; permit review is also when a plan reviewer checks your footing depth and guardrail design.
How deep do deck footings need to go?
Footings need to reach below your area's frost line so winter freeze-thaw cycles can't heave the deck, and frost depth is set locally — commonly anywhere from 12 to 48 inches depending on climate. Your building department can give you the exact number for your address; it is not a figure this calculator can safely guess at a national level.
Is composite decking really worth the higher upfront cost?
Composite typically runs about twice the material cost of pressure-treated pine per square foot, but it skips the sand-and-restain cycle wood needs roughly every 2–3 years. Price a decade of stain, sealer, and a weekend of labor into the wood column and the total cost of ownership gap narrows considerably — composite tends to win on time, wood tends to win on sticker price.
What share of a deck budget is labor versus materials?
In pro mode this calculator applies $15–$25 per square foot of labor against $5–$19 per square foot of materials depending on decking choice. For pressure-treated pine that puts labor at roughly three-quarters of the structure cost; for pricier composite or PVC decking, materials can approach or exceed half the total.
Why does building over 30 inches high cost more?
Once the deck's walking surface is 30 inches or more above grade, most residential codes require a graspable guardrail (typically 36–42 inches tall) and inspectors generally expect more robust, sometimes engineered, footings. This calculator applies a 10% multiplier to the structure cost once you select "30 in and over" to reflect that added guardrail and footing work.
How many deck boards do I need for a given square footage?
Divide your deck area by the coverage of one board — a standard 16-ft board with a 5.5-in face covers about 7.33 square feet — then add your waste percentage for cuts and round up, since boards are only sold whole. For the 192-sq-ft example on this page that's 29 boards at the default 10% waste.
How much does it cost to build a deck?
Using this page's own defaults: a contractor-built 12×16 ft (192 sq ft) pressure-treated deck runs $5,290–$8,836 — $27.55–$46.02 per square foot — and the same deck in composite runs $7,442–$12,372. Size, railing length, stairs, and the wood-vs-composite choice move the number, which is why the calculator prices your exact configuration instead of quoting one national average.
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