Board Foot Calculator for Lumber Pricing
Thickness times width times length in feet, divided by 12. Use the nominal dimensions, the 2 and the 6 in a 2x6, not the real 1.5 by 5.5, because that is how the unit is defined and how the yard prices it.
Worked example
These are the figures the calculator opens with and the answer it gives. Change anything above and every number below moves with it.
- Thickness, nominal2 in
- Width, nominal6 in
- Length12 ft
- How many pieces20
- Price per board foot, 0 to skip0 $
Total board feet240 bf
| Board feet per piece | 12 |
|---|---|
| Pieces | 20 |
| Total board feet | 240 |
| Total linear feet | 240 lf |
What this calculator assumes
- A board foot is nominal thickness times nominal width times length in feet, divided by 12. Use the nominal size, the 2 and the 6 in a 2x6, not the real 1.5 by 5.5.
- Hardwood is sold by the board foot. Softwood framing is usually sold by the piece, so this is for pricing and for comparing two quotes written differently.
A board foot is a volume, not a length
One board foot is 144 cubic inches: a piece 1 inch thick, 12 inches wide, 12 inches long. A 2x6 twelve feet long is 2 x 6 x 12 / 12, which is 12 board feet.
That is why a linear foot price and a board foot price cannot be compared directly. Two quotes for the same job written in different units are not comparable until one is converted, and that conversion is what this page is for.
Hardwood, and the quarter system
Rough hardwood is sold in quarters of an inch: 4/4 is one inch, 5/4 is an inch and a quarter, 8/4 is two inches. That measurement is taken rough, before surfacing, so a 4/4 board surfaced two sides arrives at 13/16 and is still sold and priced as 4/4.
Random width hardwood is tallied board by board. If a supplier quotes $6.50 a board foot, the price is per board foot of rough measure, and what lands on your truck is thinner than the number.
Questions people ask
How do you calculate board feet?
Nominal thickness in inches times nominal width in inches times length in feet, divided by 12. A 2x8 ten feet long is 2 x 8 x 10 / 12, which is 13.33 board feet.
Do I use nominal or actual dimensions?
Nominal. This calculator takes the nominal size, the 2 and the 6 in a 2x6.
How many board feet in a 2x4x8?
Five and one third. 2 x 4 x 8 divided by 12 equals 5.33 board feet.
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Common sizes, worked out
The same calculator with the numbers already filled in, one page per size, each ending in its own material list.
More sizes, answered
Each row is this calculator run with those numbers when the page was built. Type the same numbers in above to see every line of the working.
| Example | What it assumes | Total board feet |
|---|---|---|
| 2x4x8 | One nominal 2x4, eight feet long. | 5.33 bf |
| 2x4x10 | One nominal 2x4, ten feet long. | 6.67 bf |
| 2x4x16 | One nominal 2x4, sixteen feet long. | 10.67 bf |
| 2x6x8 | One nominal 2x6, eight feet long. | 8 bf |
| 2x10x16 | One nominal 2x10, sixteen feet long. | 26.67 bf |