Board Foot Calculator

What Is a Board Foot Calculator?

A board foot calculator is a tool for calculating the volume of sawn lumber in board feet. It uses the thickness, width and length of a piece of wood to determine how many board feet it contains, then multiplies that figure by the number of boards when more than one piece is required.

Board feet are particularly useful when comparing quantities of dimensional lumber, estimating material requirements and working with suppliers that sell or price timber according to board footage. This calculator also provides an optional waste allowance for project planning.

Why Use a Board Foot Calculator?

Board-foot calculations involve several dimensions and unit conversions. This calculator performs those calculations automatically so you can quickly determine the lumber volume represented by one board or an entire group of identical boards.

How to Use the Board Foot Calculator

Use the calculator by entering the actual dimensions of one board and then specifying how many boards you need.

1. Enter the thickness — Enter the actual thickness of the lumber in inches.
2. Enter the width — Enter the actual width of the lumber in inches.
3. Enter the length and quantity — Enter the board length, choose whether it is measured in feet, metres or inches, and enter the number of boards.
4. Apply a waste allowance — Leave the default allowance or enter your own percentage, then select Calculate Board Feet to view the results.

How to Calculate Board Feet

The standard board-foot formula uses thickness and width in inches and length in feet. Multiply the thickness by the width and the length, then divide the result by 12. The resulting number is the board-foot volume of one board. To calculate the total for several identical boards, multiply the board-foot value by the quantity.

For example, a board that is 2 inches thick, 8 inches wide and 10 feet long contains 13.33 board feet. The calculation is 2 × 8 × 10 ÷ 12 = 13.33 board feet. If you have five identical boards, the total is approximately 66.67 board feet before any waste allowance is applied.

What Is a Board Foot?

One board foot represents a volume of lumber measuring 1 foot long, 1 foot wide and 1 inch thick. It is a volume measurement rather than a measurement of surface area or length. Consequently, lumber with the same length can contain different amounts of board footage when its thickness or width changes.

Actual Lumber Dimensions Matter

When calculating board feet, use the dimensions appropriate to the lumber being measured. Nominal timber sizes can differ from actual finished dimensions, particularly for dressed or planed lumber. Using actual measurements gives a more accurate mathematical board-foot result.

Board Foot Calculator Information

The calculator converts metres and inches of length into feet before applying the standard board-foot formula. Thickness and width are entered in inches because those units form part of the standard calculation. The result is presented as board feet and can be calculated for one board or multiple identical boards.

The optional waste allowance increases the calculated board footage to provide a planning estimate. It does not alter the physical board-foot volume of the lumber itself. Actual purchasing requirements can vary because of board defects, cutting patterns, unusable offcuts, project dimensions, available stock lengths and other factors.

Frequently Asked Questions