Deck Cost Calculator
Estimate decking material cost. Enter your deck size, board size, and a price per board.
Results
- Deck boards needed
- 29
- Deck area
- 192 sq ft
- Coverage per board
- 7.5 sq ft
Estimates only. Round up and buy a little extra to account for waste, spills, and breakage.
This deck cost calculator converts deck dimensions and board width into board count and linear feet, then prices the decking at your local rate so you can compare wood against composite honestly.
Board cost is only part of a deck. Framing, footings, fasteners, and railing typically add as much again, and railing in particular is one of the most expensive components per foot.
Also used as a decking price calculator and composite vs wood deck cost comparison.
How to use the deck cost calculator
- Enter the deck length in ft.
- Enter the deck width in ft.
- Enter the board width in in.
- Enter the board length in ft.
- Enter the gap between boards in in.
- Enter the waste factor in %.
- Optionally add a price to estimate the total project cost.
- Read your quantities instantly — no sign-up, and you can print the estimate to take to the supplier.
Worked example
Inputs
- Deck length
- 16 ft
- Deck width
- 12 ft
- Board width
- 5.5 in
- Board length
- 16 ft
- Gap between boards
- 0.125 in
- Waste factor
- 10 %
Results
- Deck boards needed
- 29
- Deck area
- 192 sq ft
- Coverage per board
- 7.5 sq ft
Using the example values above, the deck cost calculator returns 29 (deck boards needed). Change any field to match your own project and the numbers update instantly.
Wood vs. composite
Pressure-treated decking is the cheapest up front, cedar sits in the middle, and composite costs the most per board but skips the annual staining. Over a 20-year life the running costs narrow the gap considerably.
Installed deck prices commonly run $25 to $50 per square foot for treated wood and $40 to $80 for composite, with height, stairs, and railing style moving those numbers most.
How much extra should I order?
Always order a little extra. A 5% waste factor suits simple, square projects; 10% is right for most jobs; bump it to 15–20% for irregular shapes, diagonal patterns, or uneven ground. Running short almost always costs more than the leftover material.
Nominal vs actual (dry)
| Nominal | Actual |
|---|---|
| 1×4 | 3/4 × 3 1/2 in |
| 1×6 | 3/4 × 5 1/2 in |
| 2×4 | 1 1/2 × 3 1/2 in |
| 2×6 | 1 1/2 × 5 1/2 in |
| 2×8 | 1 1/2 × 7 1/4 in |
| 2×12 | 1 1/2 × 11 1/4 in |
Formula
Boards = deck area ÷ board coverage, × (1 + waste%). Board coverage = (board width + gap) × board length.
Frequently asked questions
- What gap should I leave between deck boards?
- Leave 1/8 in for kiln-dried boards; wet pressure-treated boards can be butted tight since they shrink.
- How much waste should I add?
- Add 10% for straight decks and 15% for diagonal or picture-frame patterns.
- How much does a 12x16 deck cost?
- A 192 sq ft deck typically costs $4,800 to $9,600 in treated wood, or $7,700 to $15,400 in composite, installed.
- How many deck boards do I need?
- Divide the deck width in inches by the board width plus a 1/8 to 1/4 in gap, then multiply by the number of rows needed for the deck length.
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