Board Foot Calculator
This board foot calculator finds how many board feet of lumber you have and what it costs. Enter the thickness, width, and length of a board, set the quantity, and you'll get the board feet per board and the total. Add a price per board foot and it works out the cost too. It's built for woodworking and a trip to the lumberyard, and it's free and live as you type.
- Board feet for any size
- Feet or inches
- Any quantity
- Lumber cost
- Per board & total
Last updated June 17, 2026 1 board foot = 144 cubic inches Reviewed by the Calcowa team
Enter thickness, width, and length above 0.
Use the size the lumber is sold as. Leave price at 0 to skip the cost.
1 × 6 × 8 ÷ 12 = 4 bf × 10 = 40 board feet
How do I calculate board feet?
A board foot measures lumber volume, not length, so it captures how much wood a board holds. The formula multiplies thickness in inches by width in inches by length in feet, then divides by 12, because one board foot is a 12-by-12-inch piece an inch thick, or 144 cubic inches. A 1-by-6 board 8 feet long is 1 times 6 times 8 over 12, which is 4 board feet, and ten of them total 40. If your length is in inches, you divide by 144 instead. This board foot calculator handles both, multiplies by quantity, and prices it at your rate per board foot, since that's how hardwood is sold. You won't have to run the math per board, and it's the figure the yard will quote, so you'll know what you're paying before you load the cart.
Board feet for a 1x6x8, step by step
Here's ten boards, each 1 inch thick, 6 inches wide, and 8 feet long, at 5 dollars per board foot. It's the same path the tool runs, and you'll see it match the boxes above:
- 1
Multiply the dimensions1 inch times 6 inches times 8 feet is 48.
- 2
Divide by 1248 over 12 is 4 board feet in one board.
- 3
Multiply by quantity4 board feet times 10 boards is 40 board feet.
- 4
Add the cost40 board feet times 5 dollars is 200 dollars.
Board feet for common boards
Here's the board feet in a single board at common sizes and lengths. Multiply by how many you need, which the calculator does for you, so you don't have to add them up, and it's quicker than the table when sizes are mixed.
| Board | 8 ft | 10 ft | 12 ft |
|---|---|---|---|
| 1 x 4 | 2.67 | 3.33 | 4.00 |
| 1 x 6 | 4.00 | 5.00 | 6.00 |
| 2 x 4 | 5.33 | 6.67 | 8.00 |
| 2 x 6 | 8.00 | 10.00 | 12.00 |
| 2 x 8 | 10.67 | 13.33 | 16.00 |
Frequently asked questions
Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. So a board 1 inch thick, 6 inches wide, and 8 feet long is 1 times 6 times 8 over 12, which is 4 board feet. This board foot calculator does it for any size and multiplies by your quantity, so you'll get the total without the mental math at the lumberyard.
A board foot is a volume of lumber equal to a piece 1 foot by 1 foot by 1 inch thick, or 144 cubic inches. Sawmills and lumberyards price hardwood by the board foot rather than by the piece, since boards come in odd sizes. It measures how much wood you're buying, not the length, so a thick wide board holds more board feet than a thin narrow one, and that's why two boards of the same length aren't always priced the same.
Use the size the lumber is sold as, which for rough hardwood is the actual size you measure. For softwood like a 2 by 4, the nominal name is bigger than the real 1.5 by 3.5 inches, and yards usually bill the nominal size. If you want the true wood volume, enter the actual measured dimensions instead, and the tool works either way.
Multiply the total board feet by the price per board foot, which is how hardwood is quoted. So 40 board feet at 5 dollars is 200 dollars. Enter a price above and the calculator adds the cost, which is handy for comparing boards of different sizes, since the board-foot price levels out the comparison better than a price per piece.
If your length is in inches rather than feet, the formula divides by 144 instead of 12, since a board foot is 144 cubic inches. The tool has a length unit you can switch, so you enter feet or inches and it picks the right divisor. The board-foot total comes out the same either way, just measured from the unit you have.
Yes to both. There's no sign-up, no limit, and nothing to install, since it runs in your browser. The dimensions you type stay on your device and aren't sent anywhere. Bookmark it for woodworking projects or a trip to the lumberyard, and you'll have board feet and cost a tap away.
Related calculators
More tools for materials and rooms.
Concrete, gravel, paint, tile.
Square footage calculatorArea of a room or house.
Gravel calculatorCubic yards and tons.
Buying lumber?
Total the board feet above, or browse all construction tools.