Lumber Calculator
Enter your board count and dimensions to get the total board feet, handy for ordering hardwood or mill lumber.
What your result means
Board feet is how rough and hardwood lumber is priced and ordered. It's the volume of the boards in a standard unit, where one board foot is a 1 inch by 12 inch by 1 ft piece. Dimensional softwood (2x4s and the like) is usually sold by the piece, so this is most useful for mill and hardwood orders. Add 10 to 20% waste for a custom order.
How to use this calculator
- Enter board count, length, width, thickness.
- Read board feet total.
- Use board feet for ordering custom mill lumber.
- Dimensional lumber sold by piece - this calc useful for hardwoods.
The formula
Multiply the number of boards by each board's length in feet, width in inches, and thickness in inches, then divide by 12. The 12 converts to board feet, since one board foot is 144 cubic inches.
Worked example
Say you've got 20 boards of 2x6, each 8 ft long. That's 20 times 8 times 6 times 2, divided by 12, which is 160 board feet.
Lumber pricing by species (per board foot)
| Species | Price per board foot |
|---|---|
| Pine | $2 – $4 |
| Oak | $5 – $8 |
| Walnut | $10 – $15 |
Tips & gotchas
- Board feet is (boards times length in feet times width in inches times thickness in inches) divided by 12.
- Hardwood is sold by the board foot.
- Dimensional lumber like 2x4s is sold by the piece, not board feet.
- Add 10 to 20% waste on a custom mill order.
- Nominal isn't actual: a 2x4 is really 1.5 by 3.5 inches.
Frequently asked questions
How do you calculate board feet?
Boards times length in feet times width in inches times thickness in inches, all divided by 12.
Why divide by 12?
Because one board foot is 144 cubic inches, and the formula uses feet for length, so the 12 reconciles the units.
What's the difference between board feet and linear feet?
Board feet accounts for the board's width and thickness; linear feet is just the length.
How much does one board foot cost?
Pine is $2 to $4, oak $5 to $8, and walnut $10 to $15.
Is a 2x4 actually 2 by 4 inches?
No. A nominal 2x4 is really 1.5 by 3.5 inches after milling and drying.
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