A 2-inch slab
32 board feet
Board-foot math, without the headache
Board-foot calculator
Board feet measure lumber by volume. One board foot equals 144 cubic inches. Enter your thickness, width, length, and quantity below, and we will handle the math while carrying the result into your quote request.
Enter your measurements
Formula: thickness in. x width in. x length ft. x quantity / 12.
Board feet
13.33
Before you use the number
This is a material estimate, not a final price. It does not include grade, availability, delivery, custom cuts, taxes, minimums, or handling details.
Send these measurements for a quote
Phone summary: 2 in x 8 in x 10 ft x 1 = 13.33 BF
How the formula works
Board feet are the standard way to compare lumber by volume. The math is short, so you can check it by hand or let the calculator handle it.
The formula
Thickness (in.) × width (in.) × length (ft.) ÷ 12 = board feet
For several identical boards, multiply the result by the quantity.
Ten identical boards
1 in. x 6 in. x 8 ft. ÷ 12 = 4 bd. ft. each, x 10 boards
40 board feet
A live-edge walnut slab
3 in. thick x 36 in. average width x 10 ft. long ÷ 12
90 board feet
Getting your measurements right
A good estimate starts with good numbers. Here is what to enter in each field, and the two places lumber sizing trips people up.
- Thickness (in.)
- The board's actual thickness in inches. For finished lumber, use the surfaced thickness; for softwood, use the real size, not the nominal name.
- Width (in.)
- The width in inches. For a live-edge slab that changes shape, use a representative average width.
- Length (ft.)
- The length in feet. A 96-inch board is 8 feet.
- Quantity
- How many identical pieces you need. The calculator multiplies the volume for you.
Hardwood thickness in quarters
Hardwood thickness is named in quarters of an inch. The rough thickness is close to the fraction, and the board surfaces down to a smaller finished thickness. Use the finished thickness when you calculate.
| Term | Approx. rough | Surfaced |
|---|---|---|
| 4/4 | about 1 in. | 13/16 in. |
| 5/4 | about 1 1/4 in. | 1 1/16 in. |
| 6/4 | about 1 1/2 in. | 1 5/16 in. |
| 8/4 | about 2 in. | 1 3/4 in. |
Softwood is sold by nominal size
A 2x4 is a name, not a measurement. The actual dry, surfaced size is about 1 1/2 inches by 3 1/2 inches. Use the actual size when you calculate board feet for softwood.
Live-edge slabs: use an average width
A live-edge slab changes width along its length, and the formula needs one number. Use a representative average width rather than only the widest point. Treat it as a planning estimate. The width we use for a quote depends on the slab and how it will be cut, so send your best average and we confirm the measurement for your piece.
What the number tells you, and what it does not
Board footage is a volume estimate. It is not a final price, and it does not confirm several things that still matter for your order. We settle those on your quote.
Price
Board feet are not a final price. We quote against material, grade, quantity, and delivery.
Usable yield
Volume is not the clear, defect-free material you get after surfacing and cutting.
Surfaced dimensions
Rough size differs from the finished, surfaced size.
Grade
Volume says nothing about grade or appearance.
Availability
A calculated number does not confirm a slab or species is in stock.
Project fit
Final fit depends on your build, so we confirm it together.
Common board-foot questions
Quick answers to what buyers ask most before sending measurements for a quote.
What is a board foot?+
A board foot is a measure of lumber volume. One board foot equals a piece of wood 12 inches wide, 12 inches long, and 1 inch thick, or 144 cubic inches.
How do you calculate board feet?+
Multiply thickness in inches by width in inches by length in feet, then divide by 12. If you have several identical boards, multiply that result by the quantity.
How do you measure the width of a live-edge slab?+
Use the slab's average width rather than measuring only its widest point. Live-edge slabs naturally change width along their length, so a representative average gives a more useful planning estimate. The exact width for a quote depends on the slab, so confirm it with us.
Why does board footage matter when buying lumber?+
Board footage helps you compare lumber by volume and communicate the amount of wood your project needs. It is a volume estimate, not a final quote, and it does not set price, grade, usable yield, or availability.
Can Fresno Forest Creations calculate board footage for me?+
Yes. Send the thickness, average width, length, and quantity. Fresno Forest Creations can calculate the estimated board footage and help you carry those measurements into a quote request.
Where these figures come from
The board-foot definition, formula, quarter-thickness terminology, and nominal softwood sizes are drawn from university extension publications and the national hardwood and softwood standards. Average slab width is a planning estimate, and final price, grade, usable yield, and availability still depend on your project.
- How to Measure Trees and Logs by University of Missouri Extension (publication G5050), Board-foot definition paragraph.
- Quality Control in Lumber Purchasing: Hardwood Lumber Grades (FNR-130) by Purdue University Cooperative Extension Service, Table 1, board feet and surface measure definitions.
- Quality Control in Lumber Purchasing: Surface, End, and Internal Checking (FNR-133) by Purdue University Cooperative Extension Service, Page 4, standard surfaced thicknesses.
- Rules for the Measurement and Inspection of Hardwood and Cypress by National Hardwood Lumber Association, Quarter-thickness naming system.
- Voluntary Product Standard PS 20-20: American Softwood Lumber Standard by U.S. Department of Commerce and the American Lumber Standard Committee, Section 2.16, page 11, nominal size definition and dry 2x4 example.
Written by Yori, Fresno Forest Creations. Reviewed July 16, 2026.