300 sq ft deck build or replacement
ProjectCostWise currently uses an editable planning assumption of $25–$60 per sq ft for deck build or replacement before complexity adjustments. A 300 sq ft project therefore produces a $7,500–$18,000 starting range at standard complexity. This is a planning example, not a contractor quote.
Use the deck cost calculatorHow much does it cost to build a deck in 2026?
Quick answer: Using ProjectCostWise’s current editable $25–$60 per-square-foot planning assumption, a 300 sq ft deck at standard complexity produces a $7,500–$18,000 planning range. Height, railings, stairs, framing, decking material and the rate assumptions you enter can all change the result. See how ProjectCostWise calculates planning ranges.
How to calculate deck cost
A simple starting formula is deck square footage × cost per square foot × complexity adjustment. For example, 300 sq ft multiplied by $25–$60 per sq ft gives a $7,500–$18,000 starting range before complexity changes. The estimator lets you adjust project size, rate assumptions and complexity instead of relying on one fixed national average.
Deck cost per square foot
Cost per square foot is useful for early budgeting because it scales with deck size, but it is not a guaranteed market price. A low, simple platform deck can be very different from a tall, multi-level deck with composite boards, custom railings, long stairs and difficult access.
What affects deck build or replacement cost?
- Deck size, height and structural design
- Pressure-treated, composite or other decking material
- Footings, beams, joists and framing condition
- Railings, stairs and guard requirements
- Removal and disposal of an existing deck
- Site access, slope, permits and inspections
Pressure-treated wood vs composite decking
Material choice can move the budget, but it should be evaluated as part of the full project. Composite decking often carries a higher material price, while pressure-treated wood may have a lower upfront cost. Framing, footings, railings, stairs, labor, demolition and site conditions can outweigh the decking surface itself.
Three deck scope levels to compare
Simple deck
A simpler deck may be low to the ground, rectangular, easy to access and built with economical materials and limited railing.
Standard deck
A standard deck often includes elevated framing, railings, stairs, routine footings and a mid-range decking system.
Complex deck
A complex deck may be tall, multi-level, difficult to access, heavily railed, curved or built with premium composite and custom details.
Compare your deck budget with ProjectCostWise benchmarks
For context across other home projects, see the 2026 Home Project Cost Benchmarks. It explains the modeled planning assumptions used across ProjectCostWise and distinguishes them from observed contractor-bid data.
Questions to ask before choosing a deck contractor
- Are footings and framing sized for current code requirements?
- Are railings and stairs included in the quoted scope?
- Is demolition and disposal of the old deck included?
- Who obtains permits and schedules inspections?
- Which decking and railing products are specified?
- What material and labor warranties are provided?
Calculate your deck build cost
Enter your ZIP code, planned deck size and complexity. You can adjust the pricing assumptions before calculating, then use the range as a checkpoint when contractor bids arrive.
Open the free cost estimatorFrequently asked questions
How much does it cost to build a deck?
ProjectCostWise currently uses an editable planning assumption of $25–$60 per square foot for deck build or replacement before complexity adjustments.
How do I estimate deck cost per square foot?
Multiply the planned deck area by low and high cost-per-square-foot assumptions, then adjust for complexity. The ProjectCostWise estimator lets you change all of these inputs.
What makes a deck more expensive?
Height, structural framing, railings, stairs, demolition, difficult site access, premium decking materials and permitting can all increase cost.
Does composite decking cost more than pressure-treated wood?
The material purchase price is often higher, but total project cost also depends on framing, railings, stairs, labor and site conditions.