Construction Calculator - Framing and Woodwork

Board Foot Calculator

Convert lumber dimensions into board feet.

Reviewed: August 26, 2026

Calculate Board Foot

For the Board Foot Calculator, enter thickness, width, length, pieces, and price per board foot. It converts nominal thickness, width, length, and piece count into board feet and applies the optional price per board foot.

Construction measuring tools arranged beside a residential building project

Formula used

Board feet = thickness (in) × width (in) × length (ft) × pieces ÷ 12

Board Foot Calculator measurement plan showing Thickness inches, Width inches, Length feet

Worked board foot example

Board Foot Calculator example: 1 in × 6.7 in × 5.8 ft × 13 pieces ÷ 12 = 42.1 board feet. At 4.5 per board foot, the estimate is 189.44.

Interpret the piece or volume result

Compare the computed board-foot total with the supplier's tally, but order the required pieces and cutting allowance rather than volume alone.

Cuts, defects, and stock-length effects

Random widths and lengths, live edge, surfacing, defects, moisture, and seller tally rules can make invoice board feet differ from a simple rectangular tally.

Questions specific to this calculation

What exactly is one board foot?

Use thickness and width in inches, length in feet, and the number of pieces; confirm whether the yard prices rough nominal stock or surfaced dimensions.