Deck Cost Calculator
Free deck cost calculator. Estimate decking, framing, and total material cost for wood, composite, or hardwood decks. No signup.
A deck cost calculator estimates the material cost of building a deck from its footprint and decking material, covering the deck boards plus a rough allowance for framing and fasteners.
How the estimate is built
deck area = length × widthdecking cost = deck area × price per ft²framing allowance = decking cost × percentage, where the percentage is 60% for wood and cedar, and 40% for composite and tropical hardwoodtotal material = decking cost + framing allowance
The price per square foot comes from the selected material unless you enter a custom figure, which overrides the default. This is a material-only estimate; footings, stairs, railings, permits, and labor are all outside it.
Worked example: a 16 × 12 ft pressure-treated deck
Defaults: length 16 ft, width 12 ft, pressure-treated wood at the default $3.50 per ft².
| Step | Calculation | Result |
|---|---|---|
| Deck area | 16 × 12 | 192 ft² |
| Decking cost | 192 × $3.50 | $672 |
| Framing allowance (60%) | $672 × 0.60 | $403.20 |
| Total material | $672 + $403.20 | $1,075.20 |
Switch to composite and the numbers move sharply: 192 × $9 = $1,728 for decking, plus a 40% allowance of $691.20, for $2,419 in material. The higher board price is the whole difference.
Reference: decking materials
| Material | Price per ft² | Framing allowance | Material per ft² |
|---|---|---|---|
| Pressure-treated wood | $3.50 | 60% | $5.60 |
| Cedar / redwood | $5.50 | 60% | $8.80 |
| Composite | $9.00 | 40% | $12.60 |
| Ipe / tropical hardwood | $12.00 | 40% | $16.80 |
The final column is decking plus framing, a handy figure to multiply by your area. These are the calculator’s built-in defaults and are meant as ranges, not quotes. Lumber prices move with grade and region, so enter a local figure when you have one.
What the estimate leaves out
The material figure covers decking plus a percentage for framing and fasteners. It does not size the footings. A deck carries its load through posts to concrete piers, and pier size and depth depend on soil and local code, so have the layout checked before digging. Board sizing adds waste as well: decking is usually run one direction across the joists and the last board is almost always cut.
Decking direction and layout
Deck boards run either parallel or perpendicular to the house, and the choice changes how many joists and how much board you need. Perpendicular is the most common and simplest to frame; diagonal layouts look distinctive but generate more offcuts and a higher waste factor than this estimate assumes. Confirm the layout before ordering, and add a board or two beyond the estimate for mistakes.
Common mistakes
- Quoting decking only. Joists, beams, posts, and fasteners add 40–60% to a wood deck’s material bill. Skipping them makes the estimate look cheap.
- Ignoring footings and permits. Concrete piers and inspections are real costs, especially for a raised deck.
- Forgetting stairs and railings. A deck more than a step off the ground needs guard rails, and the framing allowance does not size them.
- Treating material as the build price. Professional installation typically doubles to triples the material total.
How much material for a 16 × 12 deck?
About $1,075 in pressure-treated wood, or $2,419 in composite, using the default prices and the framing allowance. Both are material only.
Is installation included?
No. Add labor, which usually runs two to three times the material cost for a professional build.
Do I need a permit for a deck?
Most jurisdictions require one for a deck above a certain height, often around 30 inches, and for any deck attached to a house. Permits and inspections sit outside the material cost shown here.
How many footings does a deck need?
It depends on span and load, which building codes set. As a rough guide, posts are usually spaced 6 to 8 feet apart, so a 16 × 12 deck might use six to nine piers. Have the footing layout designed for your soil and local code.
Board feet are the right way to price the decking itself, which the board-foot calculator covers. The concrete calculator sizes the footings under the posts.