Concrete Calculator
- Updated Jul 2026
Use this free board foot calculator to work out the exact volume of lumber in any board, estimate the price per board foot, and total your material cost in seconds. Enter thickness, width, length, and quantity, results update instantly.
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Board Foot Calculator Tool
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Results are estimates for planning purposes. Verify quantities for structural or safety-critical work.
What is a board foot?
A board foot is the standard unit of volume used to measure and price hardwood lumber in the United States and Canada. One board foot equals a piece of wood one foot long, one foot wide, and one inch thick, in other words, 144 cubic inches, or one-twelfth of a cubic foot. Because it captures thickness, width, and length together, the board foot lets you compare boards of different sizes fairly, which is exactly what a board foot calculator is built to do.
You will see the term abbreviated several ways on invoices and price lists: BF, BDFT, or FBM (foot, board measure). A thousand board feet is written MBF, MFBM, or MBFT, common when buying in bulk. This board foot calculator handles all of these behind a single, simple result.
Board foot formula
The board foot formula is simple once your units are lined up correctly. There are two versions, depending on how you measured length:
Board feet = Thickness (in) × Width (in) × Length (ft) ÷ 12
Board feet = Thickness (in) × Width (in) × Length (in) ÷ 144
Use the first when your length is in feet, and the second when every dimension is in inches. Both give the same answer. If your measurements are in centimetres, run them through our cm to inches converter first, then use the board foot calculator above.
How to calculate board feet step by step
- Measure the board’s thickness and width in inches, and its length in feet. To switch a length from inches, use a length converter.
- Multiply the three dimensions together.
- Divide by 12 to get the board feet for one piece.
- Multiply by the number of pieces for your total board footage.
- Multiply the total by the price per board foot to get your material cost.
Nominal vs actual: use the board’s nominal (rough, pre-planed) size when calculating board feet — a “2×4” is nominally 2″ × 4″, even though its actual planed size is 1.5″ × 3.5″. Lumber is sold by nominal board feet.
Use the first when your length is in feet, and the second when every dimension is in inches. Both give the same answer. If your measurements are in centimetres, run them through our cm to inches converter first, then use the board foot calculator above.
Worked example
Say you’re buying five oak boards, each 2 inches thick, 8 inches wide, and 6 feet long, at $6.00 per board foot:
- Per board: 2 × 8 × 6 ÷ 12 = 8 board feet
- Total: 8 × 5 = 40 board feet
- Cost: 40 × $6.00 = $240.00
That’s the same math the board foot calculator runs instantly when you enter the numbers.
Common lumber sizes: board foot quick reference
These are the sizes people search for most. Values use nominal dimensions and the standard board foot formula.
| Nominal size | Calculation | Board feet |
|---|---|---|
| 2×2×12 | 2 × 2 × 12 ÷ 12 | 4.00 bf |
| 2×4×8 | 2 × 4 × 8 ÷ 12 | 5.33 bf |
| 2×4×10 | 2 × 4 × 10 ÷ 12 | 6.67 bf |
| 2×6×12 | 2 × 6 × 12 ÷ 12 | 12.00 bf |
| 1×6×8 | 1 × 6 × 8 ÷ 12 | 4.00 bf |
Board feet vs square feet vs linear feet
These three units measure different things, and mixing them up is the most common lumber-buying mistake:
- Board feet measure volume — thickness, width, and length together. Used for hardwoods and thick slabs.
- Square feet measure area — width and length only. To find a room or surface area, use our square footage calculator.
- Linear (running) feet measure length only, at a fixed width and thickness. Used for trim, dimensional softwood, and decking
Converting board feet to square feet
To convert board feet to square feet, divide by the board’s thickness in inches. A 1-inch-thick board: board feet and square feet are equal. For thicker stock, 200 board feet of 2″-thick lumber covers 100 square feet; 600 board feet of 2″ stock covers 300 square feet. To go the other way, multiply the area by the thickness in inches.
How much does a board foot of lumber cost?
Price per board foot depends heavily on species and grade. Construction softwoods like pine or fir often run a few dollars per board foot, while hardwoods such as oak, walnut, or maple can range from around $5 to $15+ per board foot. Enter your supplier’s rate into the board foot calculator to get an exact total. If your yard is running a sale, our discount calculator shows what the reduced price actually saves you.
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Frequently asked questions
How do you calculate board feet?
Multiply thickness (in) × width (in) × length (ft), then divide by 12. If all three measurements are in inches, divide by 144 instead. Both formulas give board feet — the volume of the wood.
How many board feet are in a 2x4x8?
A 2×4×8 contains 5.33 board feet: 2 × 4 × 8 ÷ 12 = 5.33.
Is a board foot the same as a square foot?
No. A square foot measures area (two dimensions), while a board foot measures volume (three dimensions). They’re only equal when the board is exactly 1 inch thick.
What does BDFT or FBM mean?
Both are abbreviations for board feet. BDFT and BF are shorthand; FBM stands for “foot, board measure.” A thousand board feet is written MBF, MFBM, or MBFT.
Should I use nominal or actual dimensions?
Use nominal (rough) dimensions. Lumber is priced by its nominal size — a 2×4 counts as 2″ × 4″ even though its planed actual size is 1.5″ × 3.5″.
How do I work out the price per board foot?
Divide the total price of a board by its board footage. To find total cost instead, multiply your total board feet by the price per board foot.
** Sources and further reading: Board foot measurement follows the standard definition of a board foot as 144 cubic inches, and lumber grading and tally practices are governed by the NHLA lumber inspection rules. Both are worth reading if you’re buying rough-sawn hardwood by the tally.