Lumber Calculator
Woodworking math is confusing. From "Board Feet" to linear pricing, we simplify the numbers so you can focus on the cut list and the craftsmanship.
Board Dimensions
Demystifying the Lumber Yard
If you walk into a hardwood dealer and ask for "five feet of walnut," they will look at you confused. They sell by the Board Foot (BF).
Unlike buying a 2x4 at a big box store (which has a fixed price per stick), fine woodworking lumber varies in width and length. Pricing by volume allows them to sell you exactly what is there. Our calculator bridges the gap, translating your project dimensions into the specific volume units that sellers use.
The Formula Explained
The standard formula for one board foot is:(Thickness" × Width" × Length') / 12
Thickness Matters
Lumber is often sold as 4/4 ("four quarter", i.e., 1 inch), 5/4, 6/4 (1.5 inch), or 8/4 (2 inch). A board that is twice as thick costs twice as much per linear foot.
Length Units
Be careful! In the formula, Width is in inches, but Length is usually in FEET. If you measure length in inches, you divide by 144 instead of 12.
Linear Feet
Construction lumber (pine, fir) is often sold by the linear foot. Our calculator can help you compare: "Is this $5/board foot walnut cheaper than this $4/linear foot maple?"
Waste
Rough lumber has knots, sapwood, and cracks (checking) at the ends. Always buy 20-30% more board feet than your finished project requires.
Deck Building
Comparing composite vs cedar? Calculate total board feet required to accurately compare the bulk material cost.
Furniture Making
Building a dining table? You need 8/4 stock for legs and 5/4 for the top. Input different thicknesses to get a total project price.
Flooring
If making your own flooring from rough stock, calculate the volume of wood needed to cover your square footage.
Frequently Asked Questions
What does S4S mean?
"Surfaced 4 Sides." It means the board has been planed smooth and is ready to use. It is more expensive than "Rough" lumber because of the labor involved.
How much is a "BF"?
Prices vary wildly. Poplar might be $2.50/BF, while exotic Teak could be $30.00/BF. Always call your local supplier for current rates.
Does this work for Plywood?
No. Plywood is sold by the sheet (4x8 ft). Board feet is exclusively for solid wood lumber.
Milling Loss
Remember that "jointing" and "planing" a rough board removes material. A 1-inch rough board will end up about 3/4-inch thick after milling.
Local Processing
We do not track your project dimensions. Everything is calculated instantly in your browser.