Board Foot Calculator
Calculate board feet and lumber cost from thickness, width, length, and number of pieces.
Common Lumber: Nominal vs Actual
| Nominal Size | Actual Thickness (in) | Actual Width (in) | BF per 8 ft |
|---|---|---|---|
| 1×6 | 0.75 | 5.5 | 2.75 |
| 1×8 | 0.75 | 7.25 | 3.63 |
| 1×10 | 0.75 | 9.25 | 4.63 |
| 1×12 | 0.75 | 11.25 | 5.63 |
| 2×4 | 1.5 | 3.5 | 3.50 |
| 2×6 | 1.5 | 5.5 | 5.50 |
| 2×8 | 1.5 | 7.25 | 7.25 |
| 2×10 | 1.5 | 9.25 | 9.25 |
| 2×12 | 1.5 | 11.25 | 11.25 |
How It Works
This calculator computes board feet from your lumber dimensions. A board foot equals 144 cubic inches of wood — the standard pricing unit for hardwood lumber.
Formula (length in feet): Board Feet = (Thickness in × Width in × Length ft) / 12.
Formula (length in inches): Board Feet = (Thickness in × Width in × Length in) / 144.
Multiply by the number of pieces to get total board feet, then multiply by your price per board foot for the total cost.
Frequently Asked Questions
What is a board foot?
A board foot is a unit of volume for lumber equal to 144 cubic inches, or a piece 1 inch thick, 12 inches wide, and 12 inches long (1 ft). It is the standard unit used to price hardwood lumber and specialty wood at lumber yards and sawmills.
How do I calculate board feet?
Board feet = (Thickness in inches x Width in inches x Length in feet) / 12. If your length is in inches, use: (Thickness x Width x Length) / 144. Always use the actual (not nominal) dimensions for the most accurate result.
Should I use nominal or actual lumber dimensions?
For purchasing hardwood from a sawmill, use the rough-sawn (actual) dimensions. For dimensional lumber from a home center (2x4, 2x6, etc.), the nominal size is larger than the actual size. A 2x4 is actually 1.5 x 3.5 inches. This calculator includes a reference table for common nominal vs actual sizes.
How much does lumber cost per board foot?
Lumber prices vary widely by species. Common softwoods like pine or fir run $2-$5 per board foot. Mid-range hardwoods like red oak or poplar cost $4-$8. Premium hardwoods like walnut, cherry, or maple can be $8-$15+. Exotic species may exceed $20 per board foot.
How many board feet are in a 2x4x8?
Using nominal dimensions: (2 x 4 x 8) / 12 = 5.33 board feet. Using actual dimensions (1.5 x 3.5 x 8) / 12 = 3.5 board feet. Lumber yards typically price dimensional softwood by the piece or linear foot, not by board foot. Board foot pricing is mainly used for hardwoods.