A deck is priced per square foot of deck surface, and installed cost in most of the US runs $30 to $90 per square foot depending almost entirely on material and height.
A 12 × 16 ft deck is 192 ft². At $45 that is $8,640; at $75 it is $14,400. The gap is not vagueness — it is four or five specific decisions, and each of them is yours to make before anybody quotes.
Typical US figures. Labor-heavy regions and permit-heavy jurisdictions sit at the top of each range.
Where the money goes
| Line | Share of a typical build |
|---|---|
| Framing lumber and hardware | 20–25% |
| Decking boards | 20–30% |
| Footings and posts | 10–15% |
| Railings and stairs | 15–25% |
| Labor above material | 30–40% |
The line people shop hardest is decking boards, which is about a quarter of the job. The lines that actually decide the price are height and railing length, and neither appears on a store shelf.
The five things that move it
1. Height off the ground. A deck under 30 inches usually needs no guard rail at all, which removes an entire cost line. Above that, guards are code and they are expensive per linear foot. Above 6 ft or so the posts get bigger, the bracing gets real, and some jurisdictions want an engineer's stamp.
The jump from a 24-inch deck to a 36-inch deck is the single biggest step change in deck pricing, and it is often a matter of two steps rather than one.
2. Decking material.
| Decking | Material, per ft² |
|---|---|
| Pressure-treated pine | $2–$5 |
| Cedar | $5–$9 |
| Composite, entry | $6–$10 |
| Composite, capped premium | $9–$15 |
| PVC | $10–$16 |
| Ipe / hardwood | $12–$22 |
That is board cost only. Labor is broadly the same for all of them, and hidden fastener systems add $1–$2 per ft² on top for composite and hardwood.
3. Shape. A rectangle is the cheapest deck per square foot that exists. Angles, curves, multiple levels, and picture-frame borders all add cutting time, waste and blocking. A 45° corner costs more than the square footage it removes.
4. Railing. Pressure-treated wood rail runs $25–$45 per linear foot installed. Composite $50–$85. Aluminum $60–$110. Cable rail $100–$180. Glass more again.
A 12 × 16 deck with railing on three sides is 40 linear feet. In cable rail that is $4,000–$7,200 — potentially more than the deck surface itself.
5. Stairs. Roughly $150–$350 per step installed — and the riser count is fixed by the deck height, and every flight over three risers needs its own handrail. A deck 4 ft off the ground is 6 or 7 steps, which is a $1,000–$2,500 line that never appears in a per-square-foot estimate.
What does not move it much
Joist spacing. Going from 16″ to 12″ on center adds a third more joists — real money in lumber, but joists are a fifth of the job, so the total moves maybe 5%. If the decking needs 12″ spacing (many composites do at 45° layouts), it is not optional anyway. What spans at what spacing is worth checking before the lumber order rather than after.
Board width. 5/4×6 and 2×6 cost similar per square foot covered. The choice is about feel underfoot and joist spacing tolerance, not price.
The lines that get left out of quotes
- Permit and inspection — $150 to $800 depending on jurisdiction, and a deck almost always needs one
- Demolition of an existing deck — $5–$15 per ft²
- Ledger flashing — small money, and the single most safety-critical detail on the whole structure
- Site work — sloped ground, rock, tree roots, or no machine access all add hours to the footing day
- Finish on wood decking — stain or oil within the first year, then every two to three years
Comparing quotes honestly
Divide every quote by the same deck area, and ask each contractor for three numbers: footing count and size, joist size and spacing, and railing linear footage.
Two quotes that differ by 30% almost always differ on those three, not on labor rate. Board and fastener counts for your exact deck settle the material half of it before anyone arrives.