Deck Calculator

Estimate the decking boards, joists, beams, and screws you need for your deck — and compare total costs across Pressure-Treated, Cedar, and Composite decking options.

Deck Calculator

Deck Length (ft)

Deck Width (ft)

Waste Factor (%)

Board Length (ft)

Pricing (edit to match local rates)

PT Board ($/board, 12ft)

Cedar Board ($/board, 12ft)

Composite ($/board, 12ft)

2×8 Joist ($/LF)

2×10 Beam ($/LF)

Screws ($/5-lb box)

Deck Structure

Deck Area

240 sq ft

48 Pressure-Treated boards (12ft, incl. 10% waste)

Joists (2×8)

10 joists

16″ OC, each 20ft long

Beams (2×10)

2 beams

24 total LF

Deck Screws

3 boxes

~840 screws (5-lb boxes)

Best Total Cost

$1,313.00

Pressure-Treated

Purchase Option	Quantity	Est. Cost
Pressure-TreatedBest value	48 boards	$1,313.00
Cedar	48 boards	$1,889.00
Composite	48 boards	$2,273.00

Cheapest option: Pressure-Treated at $1,313.00This total includes decking boards, 2×8 joists, 2×10 beams, and deck screws for a 240 sq ft deck. Pressure-treated lumber is the most affordable — it's durable and widely available, but requires staining/sealing every 1–2 years.

Maintenance note for Pressure-TreatedPT lumber should be allowed to dry for several months before staining. Budget for a quality deck stain/sealer ($50–$100 for a deck this size) and plan to re-apply every 1–2 years.

This is a material estimate only. Actual board counts depend on your specific layout, railing details, and local building codes. Always consult a structural engineer for beam/post sizing and verify quantities with your lumber supplier.