Deck Joist Span Calculator
Calculate max joist span by size and spacing.
Last updated: June 2026
📋Full cost guides, how-to steps, and contractor pricing breakdowns at EstimatorSuite.com
Direction joists run across the deck.
✓ Span is adequateMax allowable span for 2x8 at 16" o.c.
13' 8"
Material Estimate
Joists needed15
Board length12 ft
Material cost$450
Based on: 2x8 Southern Pine (#2) at 16" o.c. Spans from AWC Wood Frame Construction Manual (40 psf LL + 10 psf DL). Last verified: June 2026.
Disclaimer: These estimates are for budgeting purposes only. Actual costs depend on your location, current material prices, and contractor rates. Always get 2-3 quotes from licensed contractors before starting any project.