Construction Calculator - Framing and Woodwork

Lumber Calculator

Calculate board feet and material cost for lumber orders.

Reviewed: August 26, 2026

Calculate Lumber

For the Lumber 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

Lumber Calculator measurement plan showing Thickness inches, Width inches, Length feet

Worked lumber example

Lumber Calculator example: 1 in × 4.4 in × 7.6 ft × 8 pieces ÷ 12 = 22.29 board feet. At 4.5 per board foot, the estimate is 100.32.

Interpret the piece or volume result

Use total board feet to compare lumber priced by that unit, then keep the piece-by-piece cutting list as the controlling order.

Cuts, defects, and stock-length effects

Surfacing, trim allowance, defect grade, moisture content, random lengths, and whether the seller prices nominal or actual dimensions affect purchasing.

Questions specific to this calculation

How do thickness, width, length, and piece count combine into lumber board feet?

Enter nominal thickness and width, stock length in feet, and piece count. Board-foot convention uses nominal dimensions even when dressed boards are physically smaller.