Board Foot Calculator
Convert lumber dimensions to board feet, cubic volume, and cost. Supports inches, feet, and metric sizes, plus multi-board totals.
Board Foot & Lumber Cost Calculator
For 4/4, 5/4, 6/4 lumber use 1, 1.25, 1.5, etc.
Enter to estimate total lumber cost.
Adds extra board feet for defects, knots, and trimming.
Board feet
0.00 BF / board
Total for all boards: 0.00 BF
Includes waste allowance: 0.00 BF (with 10% waste)
Volume & cost
Cubic inches: 0.00 in³
Cubic feet: 0.000 ft³
Cubic meters: 0.0000 m³
Estimated cost: $0.00 (enter price/BF)
Quick presets
What is a board foot?
A board foot (BF) is a unit of volume used in the lumber industry. It represents a board that is:
- 1 inch thick
- 12 inches wide
- 12 inches long
In other words, one board foot is:
- 144 in³ (cubic inches), or
- 1/12 ft³ (cubic foot ≈ 0.08333 ft³)
Board foot formulas
Imperial units (inches & feet)
If length is in feet:
\[ \text{Board feet} = \frac{T_{\text{in}} \times W_{\text{in}} \times L_{\text{ft}}}{12} \]
If length is in inches:
\[ \text{Board feet} = \frac{T_{\text{in}} \times W_{\text{in}} \times L_{\text{in}}}{144} \]
Metric dimensions
First convert to cubic meters, then to board feet:
\[ V_{\text{m}^3} = \left(\frac{T_{\text{mm}}}{1000}\right) \times \left(\frac{W_{\text{mm}}}{1000}\right) \times L_{\text{m}} \]
\[ \text{Board feet} = \frac{V_{\text{m}^3}}{0.002359737} \approx V_{\text{m}^3} \times 424 \]
Example: 2×4×8 board
Using nominal dimensions (2 in × 4 in × 8 ft):
\[ \text{BF} = \frac{2 \times 4 \times 8}{12} = \frac{64}{12} \approx 5.33 \text{ board feet} \]
Using actual dimensions (1.5 in × 3.5 in × 8 ft):
\[ \text{BF} = \frac{1.5 \times 3.5 \times 8}{12} = \frac{42}{12} = 3.5 \text{ board feet} \]
Board feet vs. linear feet vs. cubic feet
- Linear feet measure only length (e.g., 8 ft of 2×4).
- Board feet measure volume in lumber terms.
- Cubic feet measure volume in ft³ (useful for shipping or bulk volume).
Two boards can have the same linear feet but very different board feet if their thickness or width differs.
Nominal vs. actual dimensions
In many lumber yards:
- Hardwood is often sold by the board foot using nominal thickness (4/4, 5/4, 6/4, etc.).
- Softwood framing lumber (2×4, 2×6, etc.) has actual dimensions smaller than nominal due to surfacing.
For pricing, use the dimensions your supplier uses (often nominal). For project planning and fit, use actual measured dimensions.
Common board foot quick reference
| Size (nominal) | Length | Board feet |
|---|---|---|
| 1×6 | 8 ft | 4.00 BF |
| 1×12 | 10 ft | 10.00 BF |
| 2×4 | 8 ft | 5.33 BF |
| 2×6 | 8 ft | 8.00 BF |
| 2×10 | 12 ft | 20.00 BF |
Why add a waste factor?
Real boards have knots, checks, wane, and end-trim. Most woodworkers add 5–20% extra board feet to cover:
- Defects you will cut around
- Grain matching and layout choices
- Mis-cuts and mistakes
This calculator lets you set a waste percentage so you can order enough lumber the first time.
FAQ
How many board feet are in a cubic foot?
One cubic foot equals 12 board feet, because:
\[ 1 \text{ ft}^3 = 12 \times (1\text{ in} \times 12\text{ in} \times 12\text{ in}) = 12 \text{ BF} \]
Can I calculate board feet for a stack of mixed boards?
Yes. Calculate the board feet for each board (or group of identical boards), then add them together. You can quickly do this by adjusting the quantity field for each size and noting the total BF.
Is board foot the same as board meter?
No. Some countries use cubic meters or other metric units for lumber. This tool converts metric dimensions to board feet so you can compare prices or volumes with North American board-foot pricing.