Board Feet Calculation Guide
Master board feet calculations with our complete guide. Formula, examples, pricing tips, and quick reference.
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Board feet is the standard unit of measurement for lumber in North America. Whether you're buying hardwood for furniture, softwood for framing, or lumber for a DIY project, understanding how to calculate board feet ensures you buy the right amount and don't overpay.
What is a Board Foot?
A board foot is a unit of volume for lumber, equal to 1 inch thick × 12 inches wide × 12 inches long (144 cubic inches). It's the standard way lumberyards and suppliers measure and price wood, especially hardwoods.
Unlike linear feet (which only measures length) or square feet (which measures area), board feet accounts for all three dimensions — thickness, width, and length — giving you the true volume of wood.
The Board Foot Formula
The formula for calculating board feet is straightforward:
Board Feet = (Thickness × Width × Length) ÷ 12 (Thickness and width in inches, length in feet)
Calculation Examples
Example 1: 2×4 × 8 feet
A standard 2×4 that is 8 feet long: (2 × 4 × 8) ÷ 12 = 5.33 board feet
Example 2: 1×6 × 10 feet
A 1×6 board 10 feet long: (1 × 6 × 10) ÷ 12 = 5.0 board feet
Example 3: 2×10 × 12 feet
A 2×10 plank 12 feet long: (2 × 10 × 12) ÷ 12 = 20.0 board feet
Board Feet vs Linear Feet
Linear feet measures only length, regardless of width or thickness. It's commonly used for softwood lumber (2x4s, 2x6s) sold at home centers. Board feet measures volume and is standard for hardwood lumber.
When comparing prices: board foot pricing accounts for the actual wood volume, making it more accurate for cost comparison across different sizes. Linear foot pricing is simpler but doesn't account for material volume differences.
Board Foot Pricing
Hardwood lumber is typically priced per board foot. Prices vary by species, grade, and thickness. Common hardwoods range from $3-15 per board foot, while premium species can cost $20-50+ per board foot.
Softwood lumber at home centers is usually priced per linear foot. For example, a 2×4 might cost $0.50-1.50 per linear foot depending on wood type and treatment.
Quick Reference Chart
Here's a quick reference for common lumber sizes and their board feet per foot of length. Use this to estimate without calculating:
Tips for Accurate Estimation
Use Actual Dimensions
A 2×4 is actually 1.5 inches by 3.5 inches. For precise board foot calculations, use the actual dimensions rather than nominal sizes.
Measure Before Buying
Always measure your project and calculate board feet before going to the lumber yard. Bring your measurements to compare pricing across different sizes.
Account for Waste
Add 10-15% extra for waste, especially when working with hardwood where grain direction and defects can reduce usable material.
Summary
Board feet is essential knowledge for anyone working with lumber. The formula (T × W × L) ÷ 12 is simple once you understand it, and mastering it will save you money and prevent material shortages.
Use our free lumber calculator at the top of this guide for instant board feet calculations — just enter your dimensions and get results in seconds.
Need to Calculate Board Feet?
Use our free lumber calculator for instant results. Enter your dimensions and get board feet, linear feet, and cost estimates.
Open Lumber Calculator