Board Feet Calculator
Calculate lumber requirements and costs with precision
Nominal thickness (e.g., 1" or 2")
Nominal width (e.g., 4", 6", 8")
Average market price for lumber
Board Feet per Board
4
Total Board Feet
4
Complete lumber requirement
Linear Feet
8
Running length measurement
Estimated Cost
$20.00
Based on 1 board
Board Feet Formula
Board Feet = (Thickness × Width × Length) ÷ 12
This formula calculates the volume of wood in board feet, which is the standard measurement unit in the lumber industry. One board foot equals 144 cubic inches of wood.
What is a Board Foot?
A board foot is the standard unit of measurement for lumber in the United States and Canada. It represents the volume of a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long—equivalent to 144 cubic inches total.
The board foot measurement allows lumber vendors and contractors to standardize pricing and inventory regardless of the specific dimensions of individual boards. This makes it much easier to compare prices across different lumber sizes and species.
How to Calculate Board Feet
The calculation is straightforward once you have the three key measurements:
- Thickness (T): Measure in inches. Use nominal thickness (e.g., a "2x4" uses 2 inches)
- Width (W): Measure in inches. Use nominal width (e.g., a "2x4" uses 4 inches)
- Length (L): Measure in feet
Once you have these measurements, apply the formula: Board Feet = (T × W × L) ÷ 12. For example, a single 2×6 that is 8 feet long contains (2 × 6 × 8) ÷ 12 = 8 board feet.
Common Lumber Sizes & Board Feet
| Nominal Size | 8 ft Length | 10 ft Length | 12 ft Length |
|---|---|---|---|
| 1×4 | 2.67 bf | 3.33 bf | 4 bf |
| 1×6 | 4 bf | 5 bf | 6 bf |
| 2×4 | 5.33 bf | 6.67 bf | 8 bf |
| 2×6 | 8 bf | 10 bf | 12 bf |
| 2×10 | 13.33 bf | 16.67 bf | 20 bf |
| 4×4 | 10.67 bf | 13.33 bf | 16 bf |
Note: Actual dimensions vary slightly from nominal dimensions due to milling and moisture content adjustments.
Lumber Buying Tips
- 1.Always use nominal dimensions when calculating board feet. Actual dimensions are typically ½–¾ inches smaller due to drying and milling.
- 2.Buy 10-15% extra to account for waste, cutting errors, and defects in the lumber.
- 3.Check moisture content on the lumber you're buying. Green lumber (freshly cut) is heavier and may shrink as it dries.
- 4.Compare prices across species such as pine, oak, and cedar. Hardwoods are typically more expensive than softwoods.
- 5.Inspect boards for defects such as warping, knots, and discoloration before purchasing.
- 6.Ask about volume discounts when purchasing large quantities of lumber.