What is a Board Foot?
Understanding the standard unit for measuring lumber volume
Definition & Basic Concept
A board foot is a unit of volume used to measure lumber in North America. It represents the volume of a board that is 1 inch thick, 12 inches wide, and 12 inches long.
📏 Step-by-step visual guide to calculating board feet
Key Definition:
1 Board Foot = 144 cubic inches
Standard size: 1" thick × 12" wide × 12" long
Board Foot Formula
Board Feet = (L × W × T) ÷ 144
Where L = Length (inches), W = Width (inches), T = Thickness (inches)
Unit Conversions
- 1 Board Foot = 144 cubic inches
- 1 Board Foot = 0.00236 cubic meters
- 1 Cubic Foot = 12 Board Feet
Why Do We Use Board Feet?
Board feet have been the lumber industry standard since the 1800s. This measurement system provides a fair and consistent way to price lumber regardless of the board's dimensions.
Industry Standard
Universally accepted measurement across North America's lumber industry
Fair Pricing
Lumber is sold by price per board foot ($/BF), making comparisons easy
Project Estimation
Calculate exact material needs and costs for construction projects
How to Calculate Board Feet
Calculating board feet manually is straightforward once you know the formula. Here's a practical example:
Example: 2×4 Board (8 feet long)
• Thickness: 2 inches
• Width: 4 inches
• Length: 96 inches (8 feet × 12)
Calculation:
(2 × 4 × 96) ÷ 144 = 5.33 Board Feet
Try our free Board Foot Calculator, which supports batch calculations and automatic price totals.
Watch this step-by-step tutorial to learn how to calculate board feet:
Common Lumber Sizes Reference Table
| Nominal Size (T"×W") | Length | Board Feet |
|---|---|---|
| 1"×6" | 8 ft | 4 BF |
| 2"×4" | 8 ft | 5.33 BF |
| 2"×6" | 10 ft | 10 BF |
| 2"×8" | 12 ft | 16 BF |
| 4"×4" | 8 ft | 10.67 BF |
Nominal vs Actual Lumber Sizes (Quick Reference)
Remember: Board feet are calculated using nominal sizes, but actual dimensions are smaller due to drying and planing.
| Nominal Size | Actual Size |
|---|---|
| 1×4 | 0.75" × 3.5" |
| 1×6 | 0.75" × 5.5" |
| 1×8 | 0.75" × 7.25" |
| 2×4 | 1.5" × 3.5" |
| 2×6 | 1.5" × 5.5" |
| 2×8 | 1.5" × 7.25" |
| 4×4 | 3.5" × 3.5" |
📋 See complete chart with all sizes: Lumber Sizes: Nominal vs Actual
Frequently Asked Questions
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