What Is a Board Foot?
A board foot is a standard unit of measurement in the lumber and woodworking industry that represents the volume of wood. One board foot is equal to a board that is 12 inches long, 12 inches wide, and 1 inch thick — or 144 cubic inches. It’s commonly used to estimate the total amount of wood needed for projects such as framing, flooring, cabinetry, and furniture making.
Understanding board footage is essential when buying lumber, as many suppliers price their products per board foot. Calculating board feet allows you to compare pricing, order the correct quantity, and minimize waste. Whether you're a contractor, carpenter, or DIY woodworker, knowing how to calculate board feet will save you both time and money.
How to Calculate Board Feet
To calculate board feet, use this simple formula:
(Thickness in inches × Width in inches × Length in feet × Quantity) ÷ 12 = Total Board Feet
This formula converts all board dimensions into a volume measurement and divides by 12 to reflect the 12-inch standard used in board foot calculations.
Why Use This Free Board Foot Calculator?
- Quickly estimate lumber volume without manual calculations
- Save time and reduce errors during project planning or purchasing
- Supports bulk calculations with a quantity field for multiple boards
- Adds a waste factor to better match real-world buying
- Optimized for desktop and mobile use, so you can calculate on-site or in the workshop
Best Practices for Lumber Estimation
- Measure the actual dimensions of each board, especially if using rough-sawn lumber
- Always use the same unit system to avoid conversion errors (inches and feet)
- Include a 10–15% waste factor to account for offcuts, defects, and trimming
- Double-check measurements before placing a lumber order
- Consider the wood species and grain direction if exact yield is important
Common Uses for Board Foot Calculations
- Cabinetry and fine woodworking
- Rough carpentry and framing
- Decking, fencing, and outdoor construction
- Custom furniture and millwork
- Ordering hardwood, softwood, or exotic lumber by volume
Related Lumber & Framing Calculators
Board Foot FAQs
What is a board foot?
A board foot is a lumber volume unit equal to 144 cubic inches (12 in × 12 in × 1 in).
Do I use nominal or actual dimensions?
Use the actual measured size for best accuracy. A nominal 2×6 is commonly about 1.5 in × 5.5 in.
How do I calculate board feet?
(Thickness in inches × Width in inches × Length in feet × Quantity) ÷ 12.
How much waste should I add?
Often 10–15% for offcuts, defects, and trimming. Add more for complex cuts or higher select-grade work.
Accuracy & Review
Reviewed by: Liam Santos
Liam reviews our decking, lumber, and board foot calculators to confirm accurate framing takeoffs, dimensional lumber calculations, and waste assumptions. He focuses on ensuring estimates reflect practical framing layouts and real-world material usage.
Last updated:
See: Methodology · Data Sources · Review Board
Important Estimate Disclaimer
These estimates are for general planning purposes only and should not be used as structural design guidance. Actual lumber quantities depend on span limits, load requirements, material grade, and building code compliance.
See our Methodology and Data Sources for reference information.
Structural framing components should be verified against current code requirements before construction.