Board Foot Calculator
Use our board foot calculator to calculate total board feet for lumber. Enter number of pieces, thickness (in), width (in), and length (ft + in) to get total board feet. Includes the board foot formula and FAQs like board foot vs square foot.
What Is a Board Foot?
A board foot is a unit of volume used for lumber. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long.
Board feet measure volume, not area. That’s why board foot vs square foot can be confusing: square feet measure surface area, while board feet measure how much wood you have.
This calculator finds total board feet for multiple pieces using thickness and width in inches and length in feet and inches.
Board Foot Formula
Board feet are based on cubic inches divided by 144 (because 12 × 12 = 144 square inches in one square foot, and thickness is in inches).
Combines feet and inches into one length value.
144 converts cubic inches into board feet.
Multiply by the number of identical pieces.
A 1×6 board that’s 8 ft long is 4 board feet.
How to Calculate Board Foot
- 1
Enter the number of pieces.
- 2
Enter thickness (in) and width (in).
- 3
Enter length as feet and inches.
- 4
The calculator converts total length to inches, calculates board feet per piece, then multiplies by the number of pieces.
Frequently Asked Questions
Convert length to inches, then use BF = (thickness(in) × width(in) × length(in)) ÷ 144. Multiply by the number of pieces for total board feet.
BF = (T × W × L) ÷ 144, where T and W are in inches and L is length in inches.
Square feet measure area (surface). Board feet measure volume (how much wood). A board foot includes thickness, while a square foot does not.
It depends on thickness. A 1-inch-thick board that covers 1 square foot is 1 board foot. A 2-inch-thick board covering 1 square foot is 2 board feet.
Because it standardizes lumber volume across different thicknesses and widths, making pricing and ordering easier.