How to Calculate Board Feet: The Complete Lumber Guide

If you are buying hardwoods for furniture making, framing a house, or managing sawmill inventory, you need to know how to calculate board feet. Unlike standard construction lumber (like 2x4s) which is often sold by the linear foot, premium wood is priced by volume. Getting your board feet calculation right ensures you stay on budget and order the exact amount of material needed.

Understanding the Formula

Calculating board feet requires a simple volume formula. One board foot represents a piece of wood that is 12 inches wide, 1 foot long, and 1 inch thick (or 144 cubic inches of solid wood).

Standard Formula:
If you are measuring the thickness and width in inches, and the length in feet:
Board Feet = (Thickness × Width × Length) ÷ 12

Inches-Only Formula:
If you are measuring all three dimensions (thickness, width, and length) in inches:
Board Feet = (Thickness × Width × Length) ÷ 144

How Do You Calculate Board Feet in Lumber? (Example)

Let's say you are purchasing a piece of walnut that is 2 inches thick, 6 inches wide, and 8 feet long.

• Multiply 2 × 6 × 8 = 96
• Divide by 12 = 8 Board Feet

To skip the manual math and instantly account for project waste percentages, use our interactive Board Feet Calculator to get instant, precise material estimates.