Lumber Board Foot Calculator

The Formula

A board foot is a unit of lumber volume equal to a board 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches).

Variable Definitions

How to Use This Calculator

1. 1

   Enter the nominal thickness and width of the lumber (e.g., 2 and 4 for a 2x4).

2. 2

   Enter the length of each board in feet.

3. 3

   Enter the total number of boards needed for your project.

4. 4

   Optionally enter the price per board foot to calculate total lumber cost.

Common Applications

• Estimating board feet and total cost when buying hardwood for furniture projects like tables, cabinets, or shelves
• Calculating lumber needs for framing a wall, deck, or shed using dimensional lumber like 2x4s and 2x6s
• Comparing costs between different lumber sizes and grades for a construction or renovation project budget
• Converting between nominal and actual lumber dimensions for precise construction and joinery planning

Board feet = thickness (in) x width (in) x length (ft) divided by 12

Understanding the Concept

Board feet (bd ft) is the standard unit for pricing and selling lumber. Note that nominal dimensions are NOT actual dimensions: a 2x4 is actually 1.5 x 3.5 inches. Use nominal dimensions in the calculator, as lumber pricing is based on nominal size. Common dimensional lumber is priced in board feet, while specialty hardwoods are almost always sold by the board foot from the actual measured dimensions. Understanding the difference between nominal and actual sizes is crucial for any construction project that requires precise fit. For example, when building a stud wall, you need to account for the actual 1.5 inch thickness of a 2x4, not the nominal 2 inches. Similarly, a 1x6 board is actually 0.75 by 5.5 inches. Lumber grades also affect pricing: select structural grade is the highest quality with fewest knots, while standard grade allows more knots and imperfections. For visible projects like furniture or trim, use clear or select grade. For framing and structural work, standard grade is cost-effective and perfectly adequate. When buying hardwood for furniture projects, remember that the dimensions listed are typically the actual sawn dimensions (rough lumber), which will need to be planed and jointed down to final size at home, losing approximately 1/8 to 1/4 inch per face in the process.

Frequently Asked Questions

Sources & References