Deck Cost Calculator
What a new deck is likely to cost installed, based on deck size and a per-square-foot rate you can adjust to match quotes in your area.
Result
| Deck area | |
| Rate used | |
| Estimated installed cost |
Uses the rates you entered. Defaults are illustrative, not a contractor quote.
Units & conversions used
Deck area in square feet; metric areas are converted at 1 m² = 10.7639 ft². Cost is deck surface area (ft²) multiplied by your installed rate per square foot. What a builder's $/ft² rate includes varies by quote — framing, footings, and labor may or may not be bundled. Always check your quote's scope (see checklist below); do not assume the rate covers everything.
Formula & source
Cost range = area(ft²) × low rate … area(ft²) × high rate
Method and assumptions: area is simple rectangle geometry. The $25–$50/ft² default band is a site-selected illustrative budget range, not a verified current national average and not a fair-price benchmark. Real quotes vary widely by material, region, and project complexity — replace the defaults with local quotes whenever you have them. The default prices are illustrative assumptions, not verified current national averages.
Worked example (you can verify by hand)
Input: 16 ft × 20 ft deck, rates $25–$50/ft².
- Area: 16 × 20 = 320 ft²
- Low estimate: 320 × $25 = $8,000
- High estimate: 320 × $50 = $16,000
Expected output: estimated installed cost $8,000–$16,000 for a 320 ft² deck.
Reminder: this result uses the rates you entered. The defaults are illustrative, not a contractor quote and not a statement of fair market price.
Quote-scope checklist
Before comparing quotes, confirm each one states whether these are included :
- Decking boards / surface material
- Frame lumber and structural hardware
- Footings / foundation
- Labor (installation)
- Railings and stairs
- Permits and taxes/fees
- Old-deck removal / demolition (for replacements)
- Site access and material delivery
- Roof or cover structure (for covered decks)
Materials vs installed cost: material-only calculators and installed-cost quotes are different numbers. For example, Trex's deck cost calculator prices materials, with labor quoted separately. InchCalculator breaks out materials, labor, supplies, stairs, and removal as separate line items. Home Depot's material planning guide explains material quantities, including framing, footings, boards, fasteners and railings. When a builder gives you a single $/ft² figure, ask which of the checklist items it bundles — and do not double-count items already included when adding extras.
Limitations — what this cannot do
- One rectangle, one flat rate. Stairs, railings, benches, pergolas and multi-level sections are not itemized — builders often price those separately.
- Height and structural requirements affect the quote. This calculator does not determine permit requirements or structural design; confirm those locally.
- Permits, removal and difficult access may be included in your rate or charged separately. Confirm the scope; do not add an item twice.
FAQ
How much does a 16×20 deck cost?
320 ft² at the illustrative installed-cost assumption of $25–$50/ft² gives $8,000–$16,000. This is a budgeting aid, not a quote — material choice, height, railings, and stairs move real prices substantially. Use local itemized quotes with matching scope to set the rates; the default band does not judge whether a quote is fair.
How can I check a contractor's deck quote?
Divide the quote by your deck's square footage to get their $/ft². As a hypothetical arithmetic example only (not a fair-market-price claim): $12,800 ÷ 320 ft² = $40/ft². Then use the quote-scope checklist above to confirm what that figure includes — decking material, footing type, railing, stairs, permit fees, and whether removal or delivery are extra. Two quotes at the same $/ft² can cover very different scopes.
Why can same-size decks have different quotes?
Mainly the surface material choice, height and footing requirements, railing style, stairs, and built-ins. Identical footprints do not imply matching materials or scope. Ask each bidder to itemize so you compare like with like.
How much does replacing an old deck cost vs building new?
For a replacement, ask the builder whether removal, disposal and any substructure repair are included in the entered rate. Request separate amounts for excluded items. We don't publish a replacement cost band because removal costs vary too much by site to generalize responsibly.
How much extra does a covered or roofed deck cost?
This calculator does not itemize a roof or cover. Ask whether the entered rate includes its structure, materials and labor; keep excluded work as a separate line item. We don't publish a cover cost adder because structural requirements vary too much to generalize.
How can I save money on a new deck?
Shrink the footprint (cost scales with square footage), keep the design one level with a simple railing, and compare material options line by line. Estimate your boards first with our deck board calculator. Always get multiple itemized quotes before deciding.