Board Foot Calculator
Calculate board feet for one board or a mixed lumber project. Enter fractional thickness and width, length, quantity, optional waste and price to estimate lumber volume and purchase quantity.
Lumber list
Add one row for each different board size. Fractional dimensions such as 3/4 are supported.
Advanced settings: common lumber presets, waste & price
How to use, formulas, worked example, FAQs & lumber buying notes
How to Use the Board Foot Calculator
Add a row for each different lumber size. Enter thickness, width and length, then set the number of pieces. Use fractions such as 3/4, 1 1/2 and 6 1/2 when needed. Add a waste allowance and price per board foot in Advanced settings when you are planning a purchase.
Board Foot Formula
One board foot is a volume of 144 cubic inches. When thickness and width are in inches and length is in feet:
For multiple boards:
With an allowance:
What Is a Board Foot?
A board foot measures lumber volume, not just length or surface area. It is equal to 144 cubic inches, or a piece of wood measuring 1 inch thick × 12 inches wide × 12 inches long. Board feet are commonly used when measuring and pricing hardwood lumber because boards can have different widths and thicknesses. Procore's board foot guide provides the same definition and formula.
Board Foot Calculator for Lumber
For a lumber order with several different sizes, calculate each size separately and combine the results. ToolVault lets you add mixed rows so a project can include, for example, 4/4 hardwood boards, 5/4 stock and dimensional lumber in one estimate.
Nominal vs Actual Lumber Dimensions
This is one of the most important sources of mistakes. A board sold as a 2×4 may not measure exactly 2 inches × 4 inches after surfacing. For hardwood, quarter notation such as 4/4, 5/4, 6/4 and 8/4 refers to nominal thickness categories. Use the dimensions or billing basis used by your lumber supplier. Current board-foot calculators also emphasize the importance of distinguishing nominal from actual dimensions when estimating purchase quantities. See Nest Quantum and LumberMetric for examples of this warning.
Worked Example: 1 × 6 × 8 Lumber
Thickness = 1 in, width = 6 in, length = 8 ft.
Board feet = 1 × 6 × 8 ÷ 12 = 4.00 board feet.
For 10 identical boards, total = 40.00 board feet. With a 10% allowance, purchase quantity = 44.00 board feet.
Worked Example: 2×4 Using Actual Dimensions
If your supplier asks you to calculate from actual surfaced dimensions of 1.5 in × 3.5 in × 8 ft:
Board feet = 1.5 × 3.5 × 8 ÷ 12 = 3.50 board feet per board.
That is different from using nominal 2 × 4 dimensions. This is why the supplier's billing convention matters.
Board Feet to Cubic Feet and Cubic Metres
Because one board foot is 144 cubic inches, 12 board feet equals 1 cubic foot. ToolVault also reports the purchase quantity as cubic metres for users working in metric workflows.
How Much Waste Should I Add?
Waste depends on the project, cut plan, board quality and how much defect can be removed. There is no universal percentage that is correct for every woodworking or construction job. Use the allowance field as a planning assumption and adjust it to your project.
Frequently Asked Questions
How many board feet are in a 1×6×8 board?
Using the dimensions 1 inch × 6 inches × 8 feet, the answer is 4 board feet.
How do I calculate board feet from inches?
If length is also in inches, convert it to feet by dividing by 12, or use the equivalent cubic-inch definition: board feet = thickness × width × length in inches ÷ 144.
Can I calculate multiple board sizes?
Yes. Add a row for each different thickness, width or length and ToolVault totals them into one project estimate.
Can I use fractions such as 3/4 inch?
Yes. The calculator accepts fractional thickness and width values such as 3/4 and 1 1/2.
Should I use nominal or actual dimensions?
Use the dimension basis your supplier uses to price the lumber. Do not assume a nominal size is the same as the measured surfaced size.
Can I estimate lumber cost?
Yes. Enter your supplier's price per board foot. ToolVault multiplies it by the board feet to buy after the selected waste allowance.