Board Feet Calculator

A board foot is the standard unit for lumber volume in the US and Canada. It equals the volume of a board one foot square and one inch thick, which is 144 cubic inches. Hardwood and rough-sawn softwood are priced and sold by the board foot.

Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. For example, a 2 inch by 4 inch by 8 foot board is (2 x 4 x 8) divided by 12, which is 5.33 board feet. Multiply by the number of boards to get the total.

Use nominal dimensions, which is the size lumber is sold and priced as. A 2x4 is figured as 2 inches by 4 inches even though the surfaced board actually measures 1.5 by 3.5 inches. Suppliers quote board feet from nominal size, so this calculator uses the numbers you enter directly.

A linear foot measures length only, ignoring thickness and width. A board foot measures volume, so it accounts for how thick and wide the board is. Two boards of the same length can have very different board-foot counts if one is wider or thicker.

Cutting, trimming, and discarding defective sections mean you rarely use every board foot you buy. A waste allowance of 10 to 15 percent is common for general projects, and more for intricate cuts or lower-grade stock. Enter a percent and the calculator adds it to the board-foot total and the estimated cost.

It is an estimate, not a quote. The calculator multiplies your total board feet by the price per board foot you enter. Real invoices may differ because of grade, surfacing, length premiums, minimum order charges, delivery, and sales tax.