Board Footage Explained + A Board Foot Calculator

What's a board foot?
A board foot (bd. ft.) is the unit of measurement for hardwood lumber

T" x W" x L" divided by 144 = Bd. Ft.

Here's What To Know:

1 Bd. Ft. = 144 cubic inches

Board footage is a volume measurement

Measure by the board foot when buying random widths and random lengths

How To Plan a Project with Board Feet
or scroll down to use a basic board foot calculator

Try This Board Foot Calculator

Input Your Dimensions
(See notes at bottom for help)

Decimals or fractions okay
Decimals or fractions okay


The running total adds the board footage of multiple boards. Simply compute one board at a time at left.


  1. Only use numbers. Fractions slashes ( / ) or periods (. ) for fractional sizes. Calculator assumes your numbers are in inches, so there's no need to include double quotes ( " ).
  2. Calculator rounds lumber thickness up to the next 1/4" and lumber less than 4/4 is rounded up to 4/4. Thus, a specified thickness of 3/4" will be treated as 4/4" material.
  3. You can enter fractional wood dimensions as decimals (12.75), or as conventional fractions (12 3/4). If you use fractions, just make sure you leave a space between any leading whole number and the fraction.

The Good Ol' Fashioned Way - The Formula to Calculate Board Feet

board footage calculation

When you're looking at a stack of hardwood lumber and and you begin picking out the boards you like and want to buy, you'll notice that each board has a different width (W), and possibly a different length (L).

Let's say you've found two pieces in the 4/4 stack, one is 8" x 96" and the other is 4" x 96". Should you pay the same price for both pieces just because they're the same length?

Of course not. The first board has twice the amount of wood in it (it's twice as wide and the same length).

The unit of measurement for this kind of lumber, then, is the board foot. It's a measure of the volume of wood that's in a board.