Lumber Calculator
Board feet & framing estimates
How to Use the Lumber Calculator
The lumber calculator helps you estimate board feet for woodworking projects or calculate studs and materials for wall framing. Whether you're building a deck, framing a room, or planning a furniture project, get accurate material estimates instantly.
Understanding Board Feet
Board feet is the standard unit for measuring hardwood lumber. The formula is: (Thickness × Width × Length) ÷ 12, where all measurements are in inches and length is converted to feet. One board foot equals a piece 1" thick × 12" wide × 1' long. For a deep dive into lumber math, check out our Complete Guide to Lumber Calculations.
Wall Framing Calculations
For standard wall framing, we calculate studs based on your spacing (typically 16" or 24" on center), plus three plates (bottom plate, top plate, and double top plate). Don't forget to account for headers, cripples, and extra studs at corners and openings. You'll also need drywall and insulation to complete your walls.
Tips for Accurate Estimates
- Add 10-15% for waste, especially for rough-cut lumber
- Check local codes for required stud spacing in load-bearing walls
- Consider lumber grades when budgeting for your project
Related Calculators
Building a deck? You may also need our concrete calculator for footings, fence calculator for railings, and square footage calculator for decking coverage.
Frequently Asked Questions
Board feet = (thickness in inches x width in inches x length in feet) / 12. For example, a 2x6 board that is 8 feet long equals (2 x 6 x 8) / 12 = 8 board feet. This measurement is standard for pricing hardwood lumber.
For standard 16-inch on-center spacing, divide the wall length in inches by 16, then add 1. A 12-foot wall needs (144/16) + 1 = 10 studs, plus extra studs for corners, doors, and windows. Add 2-3 studs per door and window opening.
For a 12-foot floor joist span with typical residential loads, you would need 2x10s at 16 inches on center or 2x12s at 24 inches on center. Always consult local building codes and span tables, as requirements vary by load conditions and wood species.
Nominal size is the name (2x4), while actual size is the true dimension after drying and planing. A 2x4 actually measures 1.5 x 3.5 inches. A 2x6 is 1.5 x 5.5 inches. This difference is important for accurate project planning.
A 12x12 deck typically requires about 20 deck boards (5/4x6 at 12 feet), approximately 12 joists (2x8 or 2x10 at 12 feet), 2-3 beams, and 4-6 posts depending on your design. Add 10-15% extra for cuts and waste.
Use pressure-treated lumber for any wood that contacts the ground or is exposed to moisture, including deck framing, fence posts, and sill plates. Regular lumber is fine for interior framing and projects protected from moisture.