FixerCalc

Deck Cost Calculator

Deck cost talk is usually “per square foot,” which hides rails and stairs. This calculator shows area, then a range that adds those line items with prices you control.

Last reviewed 2026-08-25. How we calculate

Results update as you type. Units stay imperial inside the math.

Size
Pricing
Add-ons

Open edges that need a guard. A 16×12 deck against a house often needs about three sides.

Results

  • Installed cost range

    $6,460 – $11,700

  • Deck area

    192 sq ft

  • Railing

    28 ft

  • Material preset

    pt

Platform (low–high)
$3,840 – $7,680
Railing (low–high)
$1,120 – $2,520
Stairs allowance
$1,500
  • Footings, ledger flashing, permits, and rail infill codes are not fully modeled. A deck is a structural project.
  • Composite boards, hidden fasteners, and picture-frame borders raise material counts above simple area × $/sq ft.

How this calculation works

  1. Platform area is length × width. That number is for planning, not a framing takeoff of joists and beams.
  2. Installed $/sq ft ranges are loaded by material preset and applied to area.
  3. Railing is linear feet × a separate range. Stairs are a flat allowance per flight because rise, width, and landings vary too much for a honest formula from area alone.

cost = area × $/sq ft + rail lf × $/ft + flights × stair allowance

What to do next

  • Have a contractor or engineer size footings and the ledger. This page will not do that.
  • Check guard height and infill spacing in your code (often 36 in residential, 4 in sphere rule).
  • If you DIY, add fasteners, flashing, and stain as extras—the installed range assumes a crew and typical markup.

FAQ

Does “installed per square foot” include the frame?
In homeowner-facing averages, yes, it usually means a complete typical deck. Fancy in-ground spas, roof decks, and second-story builds are outside those averages—raise the high $/sq ft or get a bid.
How do I estimate railing length?
Add the lengths of edges that are not against the house. Subtract a stair opening. When unsure, walk the perimeter of the sketch with a tape on paper.

Sources

  • Area = length × width; installed cost ≈ area × $/sq ft range + railing lf × $/ft + stair allowance
  • Default PT / cedar / composite installed bands: typical US planning ranges, 2026

Cost defaults are typical US planning bands, last reviewed 2026-08-25. Edit the price fields on this page rather than treating them as a local market index.