Linear to Board Feet Calculator
Convert continuous lumber runs into total volumetric board feet for precise ordering.
How to Use This Tool
Follow these three steps to calculate accurate lumber volumes and pricing.
Enter Profile & Run
Input the nominal thickness and width of your lumber profile, followed by the total linear footage required for your project.
Add Waste & Price
Specify a waste factor percentage to account for offcuts and defects. Add your supplier's price per board foot to estimate total cost.
Review Volume
Click calculate to see your Net BF, the adjusted Gross Order accounting for waste, and the total estimated material cost.
Understanding Board Feet vs. Linear Feet
Linear feet measure only the straight-line length of a piece of wood, ignoring its thickness and width. Board feet measure the actual volume of the material. One board foot equals 144 cubic inches of wood. Sawmills and hardwood dealers price lumber by volume because wood is often milled in random widths and lengths.
Converting linear feet to board feet ensures you pay for the exact volume of material regardless of its shape. According to forestry guidelines provided by the Michigan State University Extension, this volume measurement is the undisputed standard for both standing timber and milled sawtimber.
The Standard Board Foot Formula
To calculate board feet, you must account for all three dimensions of the lumber. The standard calculation uses the wood's thickness and width in inches, multiplied by its length in feet.
Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
If you prefer to measure the entire board strictly in inches, the board foot formula changes slightly. You simply multiply the three dimensions together and divide the total by 144.
Nominal Lumber Dimensions and the Quarters System
Calculations mapping linear feet to board feet always require nominal dimensions, not the actual milled size. A standard 2x4 measures 1.5 inches by 3.5 inches, but you must use the nominal 2 and 4 in your math. Hardwood dealers use the quarter system to describe nominal lumber dimensions.
A board that is 1 inch thick is called 4/4 (four-quarters) wood. A 1.5-inch thick board is 6/4, and a 2-inch thick board is 8/4. The U.S. Forest Service establishes and utilizes these volumetric guidelines to ensure consistent pricing across the commercial lumber industry.
Applying a Lumber Waste Factor
Ordering the exact mathematical volume of wood required for a project will almost always leave you short. Woodworking involves cutting, squaring, and milling, all of which reduce the usable material. Saw blade kerf alone removes a measurable amount of wood with every pass.
You must map linear feet to board feet and then apply a lumber waste factor of 10% to 15% for standard projects using pre-surfaced wood. Increase that margin to 20% or 25% when buying rough-sawn hardwood with visible knots, sapwood, or irregular edges.
Frequently Asked Questions
What is a board foot?
A board foot is a specialized unit of volume used in the North American lumber industry. It represents a piece of wood that is 12 inches wide, 12 inches long, and 1 inch thick.
Why do you divide by 12 in the board foot formula?
When you multiply thickness in inches by width in inches by length in feet, the result mixes units of measurement. Dividing by 12 normalizes the equation to represent true board feet.
How is a board foot different from a square foot?
A square foot only measures two-dimensional surface area, such as length times width. A board foot measures three-dimensional volume, adding the material's thickness into the calculation.
Should I use actual or nominal dimensions for board feet?
Always use nominal dimensions. Lumber pricing and volume calculations are standardized around the nominal size of the board before it was dried and planed.
What does 4/4 lumber mean?
The quarter system denotes the nominal thickness of rough hardwood. A 4/4 board is 1 inch thick, an 8/4 board is 2 inches thick, and a 12/4 board is 3 inches thick.