Board Foot Calculator

What is a Board Foot?

A board foot is a standard unit of measurement for lumber volume in North America. One board foot equals a piece of wood that is 12 inches long, 12 inches wide, and 1 inch thick (144 cubic inches or approximately 2,359.74 cm³). This measurement is essential for pricing hardwood lumber, estimating project materials, and comparing costs between suppliers.

Alternatively, if all dimensions are in inches:

Understanding Lumber Thickness Notation

Hardwood lumber uses a quarter-inch notation system to indicate thickness. This system is standard throughout the industry:

Nominal vs Actual Lumber Dimensions

For softwood lumber (construction lumber), there's an important distinction between nominal and actual dimensions:

Note: When calculating board feet for hardwood, use actual thickness. For softwood, lumber yards may calculate using nominal dimensions—always clarify with your supplier.

Wood Species Weight Reference

Weight varies significantly by wood species and moisture content. The following weights are at 12% moisture content (kiln-dried standard):

Practical Applications

Cost Estimation

Lumber is typically sold by the board foot. To estimate project cost:

1. Calculate total board feet needed
2. Add 10-20% for waste, defects, and cutting
3. Multiply by price per board foot

Common Project Calculations

• Cutting Board (12" × 18" × 1.5"): 2.25 BF
• Dining Table Top (42" × 84" × 1.5"): 36.75 BF
• Bookshelf (6 shelves, 8" × 36" × 0.75"): 9 BF
• Deck (12' × 16' surface, 5/4 decking): ~200 BF

Volume Conversions

Useful conversion factors for board feet:

• 1 Board Foot = 144 cubic inches
• 1 Board Foot = 0.00236 cubic meters
• 1 Board Foot = 2,359.74 cubic centimeters
• 12 Board Feet = 1 cubic foot
• 1,000 Board Feet = 1 MBF (thousand board feet)

Frequently Asked Questions

What is a board foot?

A board foot is a standard unit of volume for lumber in North America, equal to 144 cubic inches (12 inches × 12 inches × 1 inch). It's used for pricing and measuring hardwood lumber. One board foot equals approximately 0.00236 cubic meters or 2,359.74 cubic centimeters.

How do you calculate board feet?

To calculate board feet, use the formula: Board Feet = (Length in feet × Width in inches × Thickness in inches) ÷ 12. For example, an 8-foot long, 6-inch wide, 1-inch thick board equals (8 × 6 × 1) ÷ 12 = 4 board feet.

What is the difference between nominal and actual lumber dimensions?

Nominal dimensions are the name given to lumber sizes (like 2×4), while actual dimensions are the true measurements after milling and drying. A nominal 2×4 actually measures 1.5" × 3.5". Board feet calculations for hardwood typically use actual thickness, while softwood may use nominal dimensions.

How much does a board foot of wood weigh?

Weight varies significantly by species and moisture content. At 12% moisture (kiln-dried standard), common weights per board foot are: Pine 2.1-2.6 lbs, Oak 3.1-4.7 lbs, Walnut 3.2 lbs, Maple 3.5 lbs, Cherry 2.9 lbs. Green (wet) lumber can weigh 50-100% more.

What is 4/4 lumber thickness?

The fraction notation indicates lumber thickness in quarter inches. 4/4 means four quarters (1 inch), 8/4 means eight quarters (2 inches). This system is standard for hardwood lumber: 4/4 = 1", 5/4 = 1.25", 6/4 = 1.5", 8/4 = 2", 12/4 = 3", 16/4 = 4".

How do you convert board feet to cubic feet?

To convert board feet to cubic feet, divide by 12. Since 1 board foot = 144 cubic inches and 1 cubic foot = 1,728 cubic inches, the ratio is 144/1728 = 1/12. So 12 board feet = 1 cubic foot.

Additional Resources

• Board Foot - Wikipedia
• The Wood Database - Species Information