Unit convention
The common board-foot formula uses thickness and width in inches, length in feet and quantity as the number of pieces.
Example
Ten boards that are 2 inches thick, 6 inches wide and 8 feet long equal 2 x 6 x 8 x 10 / 12 = 80 board feet.
Common mistakes
Do not use nominal dimensions if pricing is based on actual surfaced size. A board sold as 2 x 6 may measure smaller after milling.
Limitations
Nominal lumber dimensions, defects, milling loss and supplier pricing rules can differ from the simple volume estimate.
Last reviewed: 2026-05-17