Board Foot Calculator
Calculate board feet for lumber purchases. Enter thickness, width, and length to determine board footage and cost. See also Stair Calculator and Concrete Calculator.
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Board Dimensions
Cost Estimate (optional)
What Is a Board Foot?
A board foot is a unit of volume used to measure lumber. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches). Hardwood lumber and specialty woods are typically sold by the board foot, while dimensional softwood lumber (2x4s, 2x6s) is usually sold by the linear foot or per piece. Understanding board feet is essential for purchasing hardwoods, calculating project costs, and comparing lumber prices.
Board Foot Formula
Board Feet = (Thickness x Width x Length) / 12
where Thickness and Width are in inches, Length is in feet
Alternative (all inches):
Board Feet = (Thickness x Width x Length) / 144
Examples:
2x6x8 ft = (2 x 6 x 8) / 12 = 8 board feet
1x12x10 ft = (1 x 12 x 10) / 12 = 10 board feet
4x4x8 ft = (4 x 4 x 8) / 12 = 10.67 board feet
Example Calculation
10 boards of 2x6, 8 feet long:
BF per piece = (2 x 6 x 8) / 12 = 8 BF
Total = 8 x 10 = 80 board feet
At $5.00/BF: Cost = 80 x $5.00 = $400.00
Nominal vs Actual Lumber Sizes
Board feet are calculated using nominal dimensions (the name of the board), not actual dimensions. A 2x4 is actually 1.5 x 3.5 inches, but board footage is calculated as 2 x 4. This is the industry standard for pricing. When buying rough-sawn lumber from a sawmill, the nominal and actual dimensions are the same.
- 1x lumber: nominal 1 inch, actual 3/4 inch (0.75 in)
- 2x lumber: nominal 2 inches, actual 1.5 inches
- 4x lumber: nominal 4 inches, actual 3.5 inches
- 6x lumber: nominal 6 inches, actual 5.5 inches
Board Feet for Common Lumber Sizes
| Size | 8 ft | 10 ft | 12 ft | 14 ft | 16 ft |
|---|---|---|---|---|---|
| 1x4 | 2.67 | 3.33 | 4.00 | 4.67 | 5.33 |
| 1x6 | 4.00 | 5.00 | 6.00 | 7.00 | 8.00 |
| 1x8 | 5.33 | 6.67 | 8.00 | 9.33 | 10.67 |
| 1x12 | 8.00 | 10.00 | 12.00 | 14.00 | 16.00 |
| 2x4 | 5.33 | 6.67 | 8.00 | 9.33 | 10.67 |
| 2x6 | 8.00 | 10.00 | 12.00 | 14.00 | 16.00 |
| 2x8 | 10.67 | 13.33 | 16.00 | 18.67 | 21.33 |
| 2x10 | 13.33 | 16.67 | 20.00 | 23.33 | 26.67 |
| 2x12 | 16.00 | 20.00 | 24.00 | 28.00 | 32.00 |
| 4x4 | 10.67 | 13.33 | 16.00 | 18.67 | 21.33 |
Frequently Asked Questions
How do I calculate board feet?
Multiply the nominal thickness (inches) by the nominal width (inches) by the length (feet), then divide by 12. For example, a 2x6 that is 8 feet long: (2 x 6 x 8) / 12 = 8 board feet.
Why is lumber sold by the board foot?
Board feet provide a standardized volume measurement that accounts for all three dimensions. This allows fair pricing regardless of board size — a thick, narrow board and a thin, wide board with the same volume cost the same per board foot.
Do I use nominal or actual dimensions?
Use nominal dimensions for board foot calculations. A 2x6 is calculated as 2 inches by 6 inches, even though its actual dimensions are 1.5 x 5.5 inches. This is the universal industry standard for pricing lumber.
How much does hardwood cost per board foot?
Hardwood prices vary widely: red oak $4-$8/BF, white oak $5-$10/BF, maple $5-$9/BF, cherry $6-$12/BF, walnut $8-$15/BF, and exotic species $10-$30+/BF. Prices depend on grade, thickness, and availability.
What is the difference between board feet and linear feet?
Linear feet measures only length, regardless of width or thickness. Board feet measures volume (length x width x thickness). A 2x6 that is 8 feet long is 8 linear feet but 8 board feet. A 2x12 that is 8 feet long is still 8 linear feet but 16 board feet.
How do I convert linear feet to board feet?
Multiply linear feet by the nominal thickness and width, then divide by 12. For 2x6 lumber: Board Feet = Linear Feet x 2 x 6 / 12 = Linear Feet x 1. For 2x4: Board Feet = Linear Feet x 2 x 4 / 12 = Linear Feet x 0.667.
How much waste should I plan for in a woodworking project?
Plan for 15-25% waste for most woodworking projects. This accounts for defects, knots, end checks, and cutting waste. For projects requiring clear, defect-free wood, plan for 30-40% waste. Rough-sawn lumber requires additional waste allowance for planing and jointing.