Board Foot Calculator
This board foot calculator finds how many board feet are in a piece of lumber from its thickness, width, and length. Enter the board size and quantity to get total board feet, and add a price per board foot for an instant lumber cost.
Quick answer
A board foot is 144 cubic inches of wood, the same as a board 1 inch thick by 12 inches wide by 12 inches long.
What this tells you
- •A board foot is 144 cubic inches of wood, the same as a board 1 inch thick by 12 inches wide by 12 inches long.
- •With length in feet, board feet equal thickness times width times length, divided by 12.
- •Board feet use the nominal size you are charged for, not always the finished dimensions.
How to Use
- 1Enter board thickness and width in inches.
- 2Enter board length in feet.
- 3Set the quantity of identical boards.
- 4Optionally enter your price per board foot.
- 5Calculate for total board feet and cost.
How It Works
Formula
Board Feet (one board) = Thickness(in) x Width(in) x Length(ft) / 12
Total Board Feet = Board Feet x Quantity
Cost = Total Board Feet x Price per Board FootBecause a board foot equals 144 cubic inches and a foot of length is 12 inches, the calculation reduces to thickness times width in inches times length in feet, divided by 12.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
How many board feet in a 2x6x8?
Twelve 1x8x10 boards at $4.50 per bf
Board Feet for Common Lumber Sizes
Board feet per piece for standard nominal sizes at an 8-foot length.
| Nominal Size | Length | Board Feet |
|---|---|---|
| 1x4 | 8 ft | 2.67 |
| 1x6 | 8 ft | 4.00 |
| 1x12 | 8 ft | 8.00 |
| 2x4 | 8 ft | 5.33 |
| 2x6 | 8 ft | 8.00 |
| 2x8 | 8 ft | 10.67 |
| 4x4 | 8 ft | 10.67 |
Multiply by the number of boards for a total. A 2x6x8 is 8 board feet.
What Is a Board Foot?
A board foot is the standard unit for buying and pricing rough lumber, especially hardwood. One board foot is 144 cubic inches, which you can picture as a board 1 inch thick, 12 inches wide, and 12 inches long. It measures volume, so a thicker or wider board holds more board feet per running foot.
Hardwood thickness is often quoted in quarters, where 4/4 means 1 inch and 8/4 means 2 inches. Softwood from the home center is usually sold by the piece at nominal sizes, but the board foot is still how you compare value across thicknesses and species.
Common mistakes
- Entering length in inches instead of feet
- Confusing board feet with linear feet
- Using finished dimensions when you are charged for the nominal size
- Forgetting to set the quantity for multiple boards