Calculate Board Feet of Lumber
Convert lumber dimensions to board feet — the standard unit for buying hardwood. Essential for woodworking projects.
What Is a Board Foot?
A board foot is a unit of volume equal to a piece of lumber 1 inch thick × 12 inches wide × 12 inches long (144 cubic inches). The formula: Thickness (in) × Width (in) × Length (ft) ÷ 12 = Board Feet. This is how hardwood lumber is priced at lumber yards — you pay per board foot, not per board.
Common Board Foot Examples
A 1" × 8" × 8' board = 5.33 board feet. A 2" × 6" × 10' board = 10 board feet. A 4/4 (1") × 6" × 12' walnut board = 6 board feet at $12/BF = $72. Understanding board feet prevents overpaying at the lumber yard and helps you budget woodworking projects accurately.
Rough vs Surfaced Lumber
Hardwood is sold in "quarter" thicknesses: 4/4 (1"), 5/4 (1.25"), 6/4 (1.5"), 8/4 (2"). These are rough-sawn dimensions — after surfacing (planing smooth), you lose 1/8" to 1/4" per face. A 4/4 board planes to about 3/4" finished. You pay for the rough dimension but get the surfaced dimension. Factor this into your project planning.
Hardwood prices per board foot in 2026: Red Oak $5-8, White Oak $6-10, Hard Maple $6-9, Cherry $7-11, Walnut $10-16, Sapele $8-12. Prices vary significantly by region and supplier — call 3 lumber yards for quotes before committing.
