Board Foot Calculator

Calculate lumber volume in board feet and estimate project costs instantly.

Lumber Dimensions

RESULT
Total Volume
0.00
Board Feet (BF)
Total Cost: $0.00
A board foot is a specialized unit of volume for lumber in the U.S. and Canada. It is the volume of a 12" x 12" x 1" board.

What is a Board Foot?

In the lumber industry, Board Foot (BF) is the standard unit of measurement for volume. Unlike linear feet (which measures only length) or square feet (which measures area), a board foot measures the actual volume of wood.

One board foot is defined as a piece of lumber that is 12 inches wide, 12 inches long, and 1 inch thick.

How to Calculate Board Feet Manually

To calculate board feet, you multiply the thickness, width, and length, then divide by a constant. The constant depends on whether your length is in inches or feet.

If Length is in Feet (Standard):

BF =
T × W × Lft
12

If Length is in Inches:

BF =
T × W × Lin
144

Nominal vs. Actual Dimensions

When using this calculator, it's important to know if you are measuring Rough Sawn or S4S (Surfaced on 4 Sides) lumber. In a lumber yard, a "2x4" is actually 1.5" x 3.5". However, board footage is usually calculated based on the nominal size (the size before surfacing). If you are measuring rough lumber for a project, use the actual thickness and width.

Common Lumber Thicknesses (Quarters)

Lumber is often sold by "quarters" of an inch:

  • 4/4 (Four-Quarter): 1 inch thick
  • 5/4 (Five-Quarter): 1.25 inches thick
  • 6/4 (Six-Quarter): 1.5 inches thick
  • 8/4 (Eight-Quarter): 2 inches thick