Board Feet Calculator
Calculate board feet of lumber from thickness, width, and length in inches. Includes quantity multiplier.
Board Feet Calculator
Per Board
4.000
board feet
Total (1 pcs)
4.000
board feet
Board Feet Per Linear Foot (nominal sizes)
| Nominal Size | Actual Size | BF / Lin. Ft |
|---|---|---|
| 1×4 | 0.75 × 3.5" | 0.33 |
| 1×6 | 0.75 × 5.5" | 0.50 |
| 1×8 | 0.75 × 7.25" | 0.67 |
| 2×4 | 1.5 × 3.5" | 0.67 |
| 2×6 | 1.5 × 5.5" | 1.00 |
| 2×8 | 1.5 × 7.25" | 1.33 |
| 4×4 | 3.5 × 3.5" | 1.33 |
What Is a Board Foot?
A board foot (BF) is the standard unit of lumber volume in the United States, equal to a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long— 144 cubic inches. Hardwood dealers and sawmills price rough-sawn lumber by the board foot because it accounts for all three dimensions simultaneously.
The Board Feet Calculatorcomputes the total board footage of a lumber piece from its thickness, width, and length in inches. Enter your dimensions and it instantly applies the formula BF = (T × W × L) ÷ 144, returning board footage and an optional cost estimate for your full lumber order.
Board Foot Formula
The board foot calculation uses three dimensions — thickness, width, and length — all in inches, divided by 144 (the number of cubic inches in one board foot):
Where:
- T = Thickness in inches
- W = Width in inches
- L = Length in inches
- 144 = cubic inches per board foot (12 × 12 × 1)
If length is given in feet instead of inches, multiply by 12 to convert, or use the alternative form:
Worked Examples
| Thickness | Width | Length | Calculation | Board Feet |
|---|---|---|---|---|
| 1 in | 6 in | 96 in (8 ft) | (1×6×96)÷144 | 4.000 BF |
| 2 in | 8 in | 72 in (6 ft) | (2×8×72)÷144 | 8.000 BF |
| 1 in | 12 in | 144 in (12 ft) | (1×12×144)÷144 | 12.000 BF |
| 1.5 in | 4 in | 48 in (4 ft) | (1.5×4×48)÷144 | 2.000 BF |
| 3 in | 10 in | 120 in (10 ft) | (3×10×120)÷144 | 25.000 BF |
Board Feet Per Linear Foot: Common Lumber Sizes
This table shows how many board feet are contained in one linear foot of common dimensional lumber sizes. Note that nominal sizes (e.g., 2×4) differ from actual sizes(1.5 in × 3.5 in). Board footage is always calculated using actual dimensions.
| Nominal Size | Actual Size (in) | BF per Lineal Foot | BF per 8-ft Board |
|---|---|---|---|
| 1×4 | 0.75 × 3.5 | 0.219 | 1.75 |
| 1×6 | 0.75 × 5.5 | 0.344 | 2.75 |
| 1×8 | 0.75 × 7.25 | 0.453 | 3.63 |
| 1×10 | 0.75 × 9.25 | 0.578 | 4.63 |
| 1×12 | 0.75 × 11.25 | 0.703 | 5.63 |
| 2×4 | 1.5 × 3.5 | 0.438 | 3.50 |
| 2×6 | 1.5 × 5.5 | 0.688 | 5.50 |
| 2×8 | 1.5 × 7.25 | 0.906 | 7.25 |
| 2×10 | 1.5 × 9.25 | 1.156 | 9.25 |
| 2×12 | 1.5 × 11.25 | 1.406 | 11.25 |
| 4×4 | 3.5 × 3.5 | 0.851 | 6.81 |
| 4×6 | 3.5 × 5.5 | 1.340 | 10.72 |
How to Calculate Board Feet
Step-by-Step Guide
- Measure the thickness of the board in inches (use actual thickness, not nominal).
- Measure the width in inches across the face of the board.
- Measure the length in inches (or convert feet to inches by multiplying by 12).
- Multiply Thickness × Width × Length to get total cubic inches.
- Divide by 144 to convert cubic inches to board feet.
- Multiply by quantity if purchasing multiple identical boards.
Nominal vs. Actual Lumber Dimensions
Nominal size is the name given to lumber (e.g., “2×4”), while the actual sizeis smaller due to drying and surfacing (planing). A nominal 2×4 measures 1.5 in × 3.5 in actual. For board foot calculations, always use the actual measured dimensions. Rough-sawn lumber from a sawmill is typically close to nominal size.