Loan Deck Cost Estimator
Deck quotes swing wildly because "a deck" hides the material, the railing and the stairs inside one number. This estimator separates them: decking band by material, railing by the lineal foot, stairs as their own line — so you can see exactly what a quote is charging for.
Railing is priced on three open sides (length + both widths — the house side needs none) at $45–$75 per lineal foot installed; a standard stair flight at $1,200–$2,400. Ranges are typical 2026 US installed rates; the regional note below applies.
How it works
The deck platform prices per square foot by decking material: pressure-treated $45–$65, cedar $55–$80, composite $65–$100, PVC $75–$110, ipe $90–$140 per sq ft installed (structure included). Then the two lines quotes bury: railing at $45–$75 per lineal foot across the open sides, and stairs at $1,200–$2,400 a flight. On the default 16 × 12 composite deck the platform is $12,480–$19,200 of the $15,480–$24,600 total — railing and stairs are a fifth of the job, which is why two "same size" quotes can differ by thousands honestly.
Method & worked example
Method: Total = platform (area × material band: pressure-treated $45–65, cedar $55–80, composite $65–100, PVC $75–110, ipe $90–140 per sq ft) + railing (open-side lineal ft × $45–75) + stairs ($1,200–2,400 per flight).
Worked example: A 16 × 12 ft composite deck with railing (40 lineal ft) and stairs: $12,480–$19,200 platform + $1,800–$3,000 railing + $1,200–$2,400 stairs = $15,480–$24,600.
When to use this
- You are budgeting a new deck and quotes differ by thousands.
- You are deciding between pressure-treated and composite with real totals.
- A quote bundles railing and stairs invisibly and you want them itemised.
How to use it, step by step
- Enter deck length and width.
- Pick the decking material.
- Toggle railing (three open sides) and stairs to match the design.
- Compare any quote against the three itemised lines, not just the total.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Deck size | Length × width in feet | 12 × 10 small; 16 × 12 mid; 20 × 16 large |
| Material | Decking band per sq ft installed | PT $45–65; composite $65–100; ipe $90–140 |
| Railing | Priced per lineal ft on open sides | $45–75 per ft installed |
| Stairs | One standard flight to grade | $1,200–$2,400 |
Another worked example
A 12 × 10 ft pressure-treated deck with railing and stairs: platform 120 × $45–65 = $5,400–$7,800; railing 32 lineal ft = $1,440–$2,400; stairs $1,200–$2,400. Total $8,040–$12,600, mid-band $10,320 — note railing plus stairs are 40% of the low end on a small deck.
Frequently asked questions
How much does a 16 × 12 deck cost?
In composite with railing and stairs: $15,480–$24,600 installed, mid-band about $20,040. The same deck in pressure-treated runs $8,040–$12,600 at 12 × 10 — scale the platform band by your own footprint; material choice is the largest single lever you control.
How much does a 12 × 10 pressure-treated deck cost?
$8,040–$12,600 installed with railing and stairs: $5,400–$7,800 of platform, $1,440–$2,400 of railing (32 lineal ft), $1,200–$2,400 of stairs. Small decks cost more per square foot than big ones — the railing and stair lines do not shrink proportionally.
Is composite worth the extra cost?
On upkeep math, often yes over 15+ years: no staining every 1–2 years (the Deck Stain Estimator prices that habit at roughly 3 gallons and a weekend per round), no rot-board replacements. The platform premium over pressure-treated is about $20–$35 per sq ft.
Why are railing and stairs separate lines?
Because they are separate work: 40 lineal ft of railing on the default deck is $1,800–$3,000 — as much as the entire platform in cheap material. Quotes that roll them in silently cannot be compared; quotes that list them can.
What adds cost fastest?
Height (second-storey decks need taller posts, more railing, more engineering), curves and diagonal layouts (labour multipliers), and built-ins — benches, pergolas, lighting. Each is lovely; each is a line item.
🪵 Building it yourself instead?
Skip the labour share: the Deck Material Estimator counts boards, joists, posts, beams and hardware for the same deck, ready for the lumber yard.
Does a permit add much to deck cost?
Permit fees typically run $150–$600 depending on jurisdiction and project value — small next to the build, and the inspection protects the railing and footing decisions that matter.
What about a second-story deck?
Add for taller posts, doubled railing exposure, stair length and often engineering: real quotes land 25–50% above the same footprint at grade. This estimator prices grade-level decks; treat its output as the floor for elevated designs.