Board Foot Calculator
Calculate lumber volume and estimate costs for your woodworking projects
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Board Feet in Lumber Measurement
The Lumber Volume Standard
A board foot measures volume, not length or area. It equals 144 cubic inches—the volume of a board 1 foot long, 1 foot wide, and 1 inch thick. This standardized unit is essential for accurately pricing lumber and estimating material requirements.
Board Foot = (Length in feet × Width in inches × Thickness in inches) ÷ 12
Or, with all measurements in inches:
Board Foot = (Length × Width × Thickness) ÷ 144
Hardwood vs. Construction Lumber Measurement
| Aspect | Construction Lumber (Softwoods) | Hardwood Lumber |
|---|---|---|
| Dimensions Used | Nominal dimensions for calculations | Actual dimensions |
| Thickness Expression | Nominal inches (2×, 1×) | Quarter system (4/4, 8/4) |
| Example | 2×4×8′ = 5.33 board feet (using 2″ × 4″ × 8′) | 4/4×6″×8′ = 4 board feet (using 1″ × 6″ × 8′) |
| Primary Uses | Framing, construction, structural | Furniture, cabinetry, flooring, trim |
Quarter System: Hardwoods use a “quarter” system for thickness, where 4/4 (four quarters) equals 1 inch, 5/4 equals 1-1/4 inches, 6/4 equals 1-1/2 inches, and so on.
Nominal vs. Actual Dimensions
Construction lumber is sold using nominal dimensions, but the actual dimensions are smaller after drying and planing. The calculator accounts for these differences in the Standard Lumber tab.
| Nominal Size | Actual Size | Board Feet per Linear Foot |
|---|---|---|
| 1×4 | 0.75″ × 3.5″ | 0.25 |
| 1×6 | 0.75″ × 5.5″ | 0.34 |
| 1×8 | 0.75″ × 7.25″ | 0.45 |
| 2×4 | 1.5″ × 3.5″ | 0.44 |
| 2×6 | 1.5″ × 5.5″ | 0.69 |
| 2×8 | 1.5″ × 7.25″ | 0.91 |
| 2×10 | 1.5″ × 9.25″ | 1.16 |
| 2×12 | 1.5″ × 11.25″ | 1.41 |
Common Board Foot Applications
Construction Estimation
Calculate framing requirements, flooring material, and total project wood volume needs.
Furniture Making
Determine precise material quantities for furniture projects and estimate costs accurately.
Lumber Purchasing
Compare lumber prices based on volume and determine the most cost-effective options.
Woodworking Projects
Plan material needs for cabinets, shelving, and other woodworking projects.
Practical Examples of Board Feet Calculations
Example 1: Standard 2×4 Lumber
Find the board feet in ten 2×4 studs, each 8 feet long.
A 2×4 has nominal dimensions of 2 inches thick, 4 inches wide, 8 feet long.
Step 2: Apply the formulaBoard Feet = (Thickness × Width × Length in feet) ÷ 12
Board Feet = (2 × 4 × 8) ÷ 12 = 64 ÷ 12 = 5.33 board feet per stud
Step 3: Multiply by quantityTotal Board Feet = 5.33 × 10 = 53.3 board feet
Example 2: Hardwood for a Table Top
Calculate board feet for maple boards for a table top: three pieces of 8/4 stock, each 8″ wide and 6′ long.
8/4 hardwood = 2 inches thick
Width = 8 inches
Length = 6 feet
Step 2: Apply the formulaBoard Feet = (2 × 8 × 6) ÷ 12 = 96 ÷ 12 = 8 board feet per board
Step 3: Multiply by quantityTotal Board Feet = 8 × 3 = 24 board feet
Conversions from Board Feet
To Cubic Feet
Since 1 board foot = 1/12 cubic foot
To Square Feet (at 1″ thickness)
For 1″ thick lumber, 1 board foot covers 1 square foot
Tips for Accurate Board Foot Estimation
Include Waste Allowance
Add 10-15% to your total board footage for waste from cutting, defects, and mistakes.
Use Accurate Dimensions
For hardwoods, measure the actual width at its narrowest point for accurate estimates.
Understand Pricing Methods
Verify whether the lumber price is per board foot or per linear foot to avoid estimation errors.
Account for Surfacing
If planning to surface rough lumber, add extra thickness for material removed during planing.
Log Volume Estimation
The board foot content of logs is estimated differently than dimensional lumber. Three common methods are:
Doyle Scale
Commonly used in the southern United States, the Doyle scale underestimates small logs and is more accurate for larger diameter logs.
Scribner Scale
One of the oldest log rules in the US, the Scribner scale estimates board feet by diagramming the cross-section of a log.
International 1/4″ Scale
Considered the most accurate for modern sawmills, this scale accounts for a 1/4″ saw kerf and provides the most realistic yield estimates.