How do I calculate decking boards needed?

Calculate deck square footage (length × width). Account for board width and spacing (typically 1/8-1/4" gaps). Add 10-15% for waste from cuts and damaged boards. Consider board run direction—perpendicular to joists.

How far apart should deck joists be spaced?

Standard spacing is 16" on center for most decking materials. Composite decking may require 12" spacing—check manufacturer specs. Closer spacing provides more support and reduces bounce but uses more lumber.

What size boards should I use for deck framing?

Joists: typically 2×8 or 2×10 depending on span, Beams: 2×8, 2×10, or doubled/tripled, Posts: 4×4 or 6×6 depending on height and load. Consult span tables for your specific situation and local codes.

How much does it cost to build a deck?

Pressure-treated wood: $15-30/sq ft, Composite: $30-60/sq ft, Cedar or redwood: $25-50/sq ft, PVC: $35-70/sq ft. Costs include materials and installation. DIY saves 30-50% on labor. Add 10-20% for railings, stairs, and features.

Do I need a permit to build a deck?

Most decks require building permits, especially if attached to house or over 30" high. Permits ensure code compliance for safety. Requirements vary by location—check local building department before starting construction.

Everyday

Deck Calculator

Estimate materials for a simple rectangular deck.

Length (ft)

Width (ft)

Enter dimensions

How to Use This Calculator

Measure Deck Dimensions

Measure the length and width of your planned deck in feet. Consider shape—break complex decks into rectangular sections and calculate each separately.

Choose Decking Material

Select material type (pressure-treated, composite, cedar) and board size (5/4×6, 2×6, etc.). This affects spacing requirements, cost, and number of boards needed.

Calculate Decking Boards

Enter deck size and board specifications. The calculator determines linear feet of decking needed, accounting for board width and spacing gaps. It includes waste factor.

Calculate Framing Materials

Based on deck size, calculate joists (spaced 16" on center), beams, posts, and hardware. Don't forget concrete for footings, joist hangers, screws/nails, and flashing tape.