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Board Foot Calculator — Lumber Purchases

Calculate board feet for lumber purchases. Get total board footage, cost, and waste-adjusted quantities.

Shortest dimension of the area

Longest dimension of the area

Number of items needed

Optional — leave 0 to skip cost

How We Calculate This

A board foot is the standard unit for pricing hardwood lumber. This calculator computes board footage from the thickness, width, and length of each board.

Formula

Board Feet = Thickness (in) × Width (in) × Length (ft) ÷ 12

Standard thicknesses

  • 4/4 = 1 inch (finishes to ~13/16")
  • 5/4 = 1.25 inches
  • 6/4 = 1.5 inches
  • 8/4 = 2 inches (finishes to ~1-13/16")
  • 12/4 = 3 inches

Frequently Asked Questions

Last updated: March 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.