Board Foot Calculator
Calculate board feet from a board's thickness, width and length, with a quantity and a price per board foot for the total cost. Or convert linear feet to board feet for standard lumber sizes like 2x4 and 2x6.
How to calculate board feet
A board foot is a piece of lumber 12 inches by 12 inches by 1 inch, or 144 cubic inches. To find the board feet in a board:
Board feet = thickness (in) × width (in) × length (ft) ÷ 12
- Measure the thickness and width in inches.
- Measure the length in feet. If you measured it in inches, divide by 12 first, or divide the final product by 144 instead of 12.
- Multiply the three numbers together and divide by 12.
- Multiply by the number of identical pieces, then by the price per board foot for the cost.
Examples
- A 2×4 that is 8 ft long: 2 × 4 × 8 ÷ 12 = 5.33 board feet. Run this example →
- A 1×12 that is 10 ft long: 1 × 12 × 10 ÷ 12 = 10 board feet. Run this example →
- An 8/4 hardwood board, 6 in wide and 8 ft long: 2 × 6 × 8 ÷ 12 = 8 board feet. Run this example →
Board feet in common lumber sizes
Board feet use the nominal size, the name the lumber is sold under. The finished (actual) size is smaller because the board is planed after sawing. Pick your size and length below to see the board feet in one piece.
| Nominal size | Actual size (in) | Per linear ft | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|---|---|
| 1×4 | 0.75 × 3.5 | 0.33 | 2.67 | 3.33 | 4 | 5.33 |
| 1×6 | 0.75 × 5.5 | 0.5 | 4 | 5 | 6 | 8 |
| 1×8 | 0.75 × 7.25 | 0.67 | 5.33 | 6.67 | 8 | 10.67 |
| 1×10 | 0.75 × 9.25 | 0.83 | 6.67 | 8.33 | 10 | 13.33 |
| 1×12 | 0.75 × 11.25 | 1 | 8 | 10 | 12 | 16 |
| 2×4 | 1.5 × 3.5 | 0.67 | 5.33 | 6.67 | 8 | 10.67 |
| 2×6 | 1.5 × 5.5 | 1 | 8 | 10 | 12 | 16 |
| 2×8 | 1.5 × 7.25 | 1.33 | 10.67 | 13.33 | 16 | 21.33 |
| 2×10 | 1.5 × 9.25 | 1.67 | 13.33 | 16.67 | 20 | 26.67 |
| 2×12 | 1.5 × 11.25 | 2 | 16 | 20 | 24 | 32 |
| 4×4 | 3.5 × 3.5 | 1.33 | 10.67 | 13.33 | 16 | 21.33 |
| 6×6 | 5.5 × 5.5 | 3 | 24 | 30 | 36 | 48 |
Sizes and finished dimensions as of 2026-09; they can vary slightly by mill.
Hardwood board feet and quarter thickness (4/4, 8/4)
Hardwood is sold by the board foot, with thickness quoted in quarters of an inch. Enter the thickness in inches in the calculator above. Ask your supplier how they measure and round width and length, and for boards of different sizes, calculate each one and add the board feet.
| Quarter notation | Thickness (in) | Board feet per sq ft of face |
|---|---|---|
| 4/4 | 1 | 1 |
| 5/4 | 1.25 | 1.25 |
| 6/4 | 1.5 | 1.5 |
| 8/4 | 2 | 2 |
| 10/4 | 2.5 | 2.5 |
| 12/4 | 3 | 3 |
| 16/4 | 4 | 4 |
How to work out the cost by the board foot
Total cost = total board feet × price per board foot. For example, 10 pieces of 1×6×8 ft are 40 board feet, so at $5.00 per board foot (an example price) they cost $200.00. This calculator does not know current prices; enter your supplier's quote in the price field. It does not include tax, delivery or extra for cut-off waste.
Convert linear feet to board feet by lumber size
If you have a length of a standard size, the second form above converts in either direction using the nominal size. It also shows the finished size and the face coverage of the board, which uses the actual width because that is what covers a deck or wall.
- Linear feet → board feet: nominal thickness × nominal width × length (ft) ÷ 12.
- Board feet → linear feet: board feet × 12 ÷ (nominal thickness × nominal width).
- Face coverage: actual width ÷ 12 × length (ft).
Frequently asked questions
How do you calculate board feet?
Multiply the board's thickness in inches by its width in inches by its length in feet, then divide by 12. A 2x4 that is 8 feet long is 2 × 4 × 8 ÷ 12 = 5.33 board feet. For several identical boards, multiply the result by the number of pieces.
How many board feet are in a 2x4x8?
5.33 board feet: 2 × 4 × 8 ÷ 12. Lumber yards count a 2x4 by its nominal 2-inch by 4-inch size, not its smaller finished size of 1.5 by 3.5 inches.
How many board feet are in a 2x6, 2x8, 2x10 and 2x12?
A 2x6 is 1 board foot per linear foot, a 2x8 is 1.33, a 2x10 is 1.67 and a 2x12 is 2. An 8-foot piece is 8, 10.67, 13.33 and 16 board feet.
Do board feet use nominal or actual size?
Nominal. Dimensional lumber is measured and priced by the size it is sold as, so a 2x6 counts as 2 inches by 6 inches even though it is milled to 1.5 by 5.5 inches. Enter the nominal thickness and width in the calculator to match what the yard charges. For hardwood, use the rough thickness it is sold at, such as 4/4 or 8/4.
How do you calculate board feet when the length is in inches?
Multiply thickness, width and length, all in inches, then divide by 144. A board 1 inch thick, 6 inches wide and 96 inches long is 1 × 6 × 96 ÷ 144 = 4 board feet, the same as 1 × 6 × 8 ft ÷ 12. In the calculator, switch the length unit to inches.
How do you calculate the cost of lumber by the board foot?
Multiply the total board feet by the price per board foot. 10 pieces of 1x6x8 ft are 40 board feet, so at $5.00 per board foot they cost $200.00. The price is only an example; enter your supplier's price in the calculator.
What do 4/4 and 8/4 mean on hardwood?
Hardwood thickness is quoted in quarters of an inch: 4/4 is 1 inch, 5/4 is 1.25 inches, 6/4 is 1.5 inches and 8/4 is 2 inches. Enter that thickness in inches to get board feet, for example 8/4 (2 in) × 6 in wide × 8 ft long is 8 board feet.
How many board feet are in a cubic foot?
12. A board foot is a piece 12 inches by 12 inches by 1 inch, which is 144 cubic inches, or one twelfth of a cubic foot (1,728 cubic inches).
What is the difference between board feet and linear feet?
Linear feet measure length only. Board feet measure volume, so thickness and width count too: 10 linear feet of a 2x12 is 20 board feet, while 10 linear feet of a 1x4 is 3.33.
How many linear feet is 100 board feet of 2x6 lumber?
100 linear feet, because a 2x6 is exactly 1 board foot per linear foot (2 × 6 ÷ 12). For other sizes, divide the board feet by the size's board feet per linear foot, for example 100 ÷ 0.67 = 150 linear feet of 2x4.
Limitations
The calculator treats every piece as identical and uses the sizes you enter. Actual (finished) dimensions can vary slightly by mill and by whether lumber is surfaced or rough-cut, and suppliers may round widths and lengths their own way, so confirm exact sizes and measuring practice with your supplier. It does not look up prices, apply volume pricing tiers or add an allowance for waste.
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