Board Foot Calculator
Board Feet = Length (ft) × Width (in) × Thickness (in) / 12 × Number of PiecesA Board Foot Calculator is an essential tool for anyone working with lumber, whether you’re a professional carpenter, a builder, or a DIY enthusiast. This article provides an in-depth look at what a board foot is, why accurate calculation matters, and how to use a Board Foot Calculator. We’ll also walk through step-by-step calculations so you can confidently measure lumber for your projects.
What is a Board Foot?
A board foot is a unit of measurement used for lumber in North America and by many woodworking professionals globally. It represents a volume of wood equal to a board that is 1 foot long, 1 foot wide, and 1 inch thick.
Board Foot Formula
The formula to calculate board feet for one piece of lumber is:Board Feet=Thickness (in inches)×Width (in inches)×Length (in feet)12Board Feet=12Thickness (in inches)×Width (in inches)×Length (in feet)
- Thickness: Measured in inches
- Width: Measured in inches
- Length: Measured in feet
Why Calculate Board Feet?
- Cost Estimation: Lumber is often sold by the board foot. Accurate calculation means you pay for exactly what you need.
- Project Planning: Board foot calculations help you determine the quantity of wood required, minimizing waste.
- Material Comparison: Standardizes different sizes and shapes of lumber for easier comparison.
How Does a Board Foot Calculator Work?
A Board Foot Calculator is a digital tool (web, mobile app, or spreadsheet) where you enter the thickness, width, and length of your lumber. The calculator uses the board foot formula to give you the total volume instantly.
Step-by-Step Board Foot Calculation Example
Let’s say you have a plank of wood:
- Thickness: 2 inches
- Width: 6 inches
- Length: 10 feet
Step 1: Multiply thickness, width, and length:2 (in)×6 (in)×10 (ft)=1202(in)×6(in)×10(ft)=120
Step 2: Divide by 12 to convert to board feet:12012=1012120=10
Result: You have 10 board feet of lumber.
Calculating Board Feet for Multiple Planks
If you have multiple planks with the same dimensions, multiply the number of planks by the board feet per plank.
For example:
5 identical planksTotal Board Feet=10 (board feet per plank)×5=50Total Board Feet=10(board feet per plank)×5=50
Board Foot Calculator Table
| Thickness (in) | Width (in) | Length (ft) | Board Feet |
|---|---|---|---|
| 1 | 12 | 8 | 8 |
| 2 | 6 | 10 | 10 |
| 1.5 | 4 | 12 | 6 |
How to Use an Online Board Foot Calculator
Most calculators are simple to use:
- Input the thickness, width, and length (usually in inches and feet).
- Select the number of boards or units if needed.
- Click “Calculate.”
- Get Results instantly in board feet.
Some calculators allow you to enter all dimensions in inches. In that case, convert the total length from inches to feet (divide by 12) before applying the board foot formula.
Manual Board Foot Calculation in Centimeters (for International Users)
If your lumber is measured in centimeters (as is common in India), convert to inches and feet:
- 1 inch = 2.54 cm
- 1 foot = 30.48 cm
Example:
Thickness: 5cm, Width: 15cm, Length: 240cm
Convert:
- Thickness: 5 ÷ 2.54 ≈ 1.97in
- Width: 15 ÷ 2.54 ≈ 5.91in
- Length: 240 ÷ 30.48 ≈ 7.87ft
Board Feet=1.97×5.91×7.8712≈7.65Board Feet=121.97×5.91×7.87≈7.65
Tips for Accurate Measurement
- Always measure thickness and width at the thickest, widest points.
- Use a measuring tape that shows both metric and imperial units for easy conversion.
- Double-check all dimensions to avoid purchasing too much or too little lumber.
Conclusion
A Board Foot Calculator ensures accuracy, efficiency, and cost-effectiveness in any woodworking or construction project. By understanding the formula, applying the steps shown above, and using digital calculators when available, you can plan your lumber needs precisely—saving both time and money on your projects.