Board Foot Calculator

How to Calculate Board Feet

A board foot is the standard unit for measuring lumber volume in the US. One board foot equals 144 cubic inches.

The formula

Board Feet = (Thickness × Width × Length × Quantity) ÷ 144

All dimensions are in inches. The divisor 144 comes from 12 × 12 (one square foot × one inch thick).

Step-by-step

1. Enter the thickness of the lumber in inches (e.g., 1 for 1-inch boards, 1.5 for 2×4 nominal).
2. Enter the width in inches.
3. Enter the length in inches (e.g., 96 for an 8-foot board).
4. Enter the quantity of boards.

Worked example

Ten boards, each 1" thick × 6" wide × 96" long. Board feet = (1 × 6 × 96 × 10) ÷ 144 = 5,760 ÷ 144 = 40 board feet.

Lumber sizing tips

Remember that nominal dimensions differ from actual: a 2×4 is actually 1.5" × 3.5". For accurate board foot calculations, use actual finished dimensions, not nominal sizes.