Board Feet vs Square Feet vs Linear Feet: Complete Comparison Guide

Confused about which lumber measurement unit to use? You’re not alone. The wood industry uses three primary measurement units—board feet, square feet, and linear feet—each serving different purposes. This comprehensive guide will help you understand the key differences, know when to use each unit, and confidently choose the right measurement for your project.

Last reviewed: November 8, 2025 by the Board Foot Calculator research team.

Quick Comparison Table

All measurements: T (thickness) and W (width) in inches, L (length) in feet.

Understanding Board Feet

Definition and Formula

A board foot is a volume measurement representing 144 cubic inches of wood. It’s the industry standard for pricing lumber, especially hardwoods and bulk purchases.

Formula: Board Feet = (Thickness × Width × Length) / 144

Where:

• Thickness (T) and Width (W) are in inches
• Length (L) is in feet
• 144 is the number of cubic inches in one board foot (12″ × 12″ × 1″)

When to Use Board Feet

Board feet are ideal for:

• Hardwood and softwood wholesale purchases: Lumber yards price by board feet for fair comparison across different sizes
• Mixed lumber orders: When buying multiple sizes, board feet provide a common metric
• Large woodworking projects: Furniture building and custom work where precise volume matters
• Inventory management: Tracking wood stock in lumber yards and workshops

Example Calculation

For a 2×6×10’ board:

• Board Feet = (2 × 6 × 10) / 144 = 120 / 144 = 0.83 board feet

For a 1×12×8’ board:

• Board Feet = (1 × 12 × 8) / 144 = 96 / 144 = 0.67 board feet

Learn more: What is a Board Foot?

Understanding Square Feet

Definition and Formula

Square feet measure the surface area of lumber, focusing on coverage rather than volume. This unit is particularly useful when thickness is consistent across your project.

Formula: Square Feet = (Width × Length) / 144

Where:

• Width (W) is in inches
• Length (L) is in feet
• Result represents the coverage area

When to Use Square Feet

Square feet work best for:

• Flooring projects: Calculating how much wood you need to cover a floor
• Wall paneling and siding: Determining coverage for vertical surfaces
• Plywood and sheet goods: Standard pricing method for sheet materials
• Decking: Estimating deck board requirements based on deck size

Example Calculation

For a 1×6×10’ floor board:

• Square Feet = (6 × 10) / 144 = 60 / 144 = 0.42 square feet

For a 120 square foot room with 1” thick flooring:

• You need 120 square feet of flooring material
• This equals 120 board feet (since thickness is 1”)

Note: Square feet and board feet are equal when thickness is exactly 1 inch.

Understanding Linear Feet

Definition and Formula

Linear feet simply measure the length of lumber, ignoring width and thickness. This is the simplest measurement unit and most common in retail settings.

Formula: Linear Feet = Length in feet

No calculation needed—just the length!

When to Use Linear Feet

Linear feet are perfect for:

• Retail hardware store purchases: Most stores price standard-sized lumber (2×4s, 2×6s) per piece or linear foot
• Trim and molding: Crown molding, baseboards, and decorative strips sold by length
• Fencing and railings: Projects where you need a specific length of standard-sized boards
• Simple projects: When you’re buying pre-cut, standard-sized lumber

Example Calculation

For an 8-foot 2×4:

• Linear Feet = 8 linear feet

For a room requiring 40 feet of baseboard:

• You need 40 linear feet of trim

Simple rule: If you’re buying standard-sized lumber at a hardware store, you’re likely paying by linear feet.

Unit Conversion Guide

Converting between these units requires additional information about the lumber dimensions. Here’s how to do it:

Board Feet ↔ Square Feet

To convert Board Feet to Square Feet:

Square Feet = Board Feet / Thickness (in inches)

To convert Square Feet to Board Feet:

Board Feet = Square Feet × Thickness (in inches)

Examples:

• 10 board feet of 1” thick lumber = 10 square feet
• 10 board feet of 2” thick lumber = 5 square feet
• 20 square feet of 1.5” thick lumber = 30 board feet

Board Feet ↔ Linear Feet

To convert Board Feet to Linear Feet:

Linear Feet = Board Feet / [(Thickness × Width) / 12]

To convert Linear Feet to Board Feet:

Board Feet = Linear Feet × [(Thickness × Width) / 12]

Examples:

• 1 linear foot of 2×4 = (2 × 4) / 12 = 0.67 board feet
• 1 linear foot of 2×6 = (2 × 6) / 12 = 1.0 board feet
• 1 linear foot of 1×12 = (1 × 12) / 12 = 1.0 board feet

Quick Conversion Table

Important: These conversions assume nominal dimensions. Actual lumber dimensions are slightly smaller.

Real-World Comparison Examples

Let’s see how these units work in practice with three common projects:

Example 1: Flooring Project

Scenario: You need to cover a 10×12 foot room (120 square feet) with 1” thick oak boards.

Using Board Feet:

• Total volume needed = 120 sq ft × 1 inch thickness = 120 board feet
• Cost at $4/board foot = $480

Using Square Feet:

• Coverage area = 120 square feet
• Cost at $4/square foot = $480

Using Linear Feet (with 1×6 boards):

• Each 1×6 board covers 0.5 sq ft per linear foot
• Total needed = 120 ÷ 0.5 = 240 linear feet
• Cost at $2/linear foot = $480

Best Choice: Square feet is most intuitive for flooring since you’re focused on coverage area.

Example 2: Furniture Building Project

Scenario: Building a bookshelf requires various lumber sizes:

• 4 pieces of 1×12×6’ (shelves)
• 2 pieces of 2×4×6’ (sides)
• 1 piece of 1×6×4’ (back support)

Using Board Feet:

• Shelves: 4 × [(1 × 12 × 6) / 144] = 4 × 0.5 = 2.0 BF
• Sides: 2 × [(2 × 4 × 6) / 144] = 2 × 0.33 = 0.67 BF
• Back: (1 × 6 × 4) / 144 = 0.17 BF
• Total: 2.84 board feet

Using Square Feet:

• Not practical—thickness varies too much between pieces

Using Linear Feet:

• Not practical—different widths make comparison difficult

Best Choice: Board feet is ideal for mixed-size lumber projects.

Example 3: Trim Installation

Scenario: Installing baseboard trim around a 12×14 foot room (perimeter = 52 feet).

Using Board Feet (with 1×4 trim):

• Board Feet = 52 × [(1 × 4) / 12] = 17.33 board feet
• Requires calculation for standard trim

Using Square Feet:

• Not commonly used for narrow trim

Using Linear Feet:

• Simply need 52 linear feet of baseboard
• Cost at $1.50/linear foot = $78

Best Choice: Linear feet is simplest and most common for trim work.

How to Choose the Right Unit

Use this decision guide to select the appropriate measurement unit:

Choose Board Feet When:

• Buying lumber in bulk from a wholesale supplier
• Working with mixed lumber sizes in a single project
• Purchasing hardwoods (oak, maple, walnut, etc.)
• You need precise volume calculations for cost estimation
• Comparing prices across different lumber dimensions

Choose Square Feet When:

• Installing flooring or decking
• Covering walls with paneling or siding
• Buying plywood or sheet goods
• Thickness is consistent across your project
• You’re focused on coverage area rather than volume

Choose Linear Feet When:

• Buying standard-sized lumber at retail stores
• Installing trim, molding, or baseboards
• Building fences or railings with uniform boards
• You want the simplest calculation
• The supplier prices by the piece or length

Pro Tip: When in doubt, ask your supplier which unit they use for pricing. This ensures you’re comparing apples to apples when shopping around.

Common Lumber Sizes Reference

Here’s a quick reference for common lumber sizes in all three units:

• Board Feet: Best for bulk purchases and mixed lumber sizes (measures volume)
• Square Feet: Best for flooring and coverage projects (measures area)
• Linear Feet: Best for standard trim and retail purchases (measures length)

Choose the unit that matches your project type and supplier’s pricing method. When in doubt, ask your supplier which unit they use, and don’t hesitate to use our calculators to verify your measurements.

Ready to calculate? Try our Board Foot Calculator to get started with your next project.

References

• USDA Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material
• National Hardwood Lumber Association. NHLA Rules for the Measurement and Inspection of Hardwoods and Cypress
• APA – The Engineered Wood Association. Engineered Wood Construction Guide

Disclaimer: This guide provides educational information about lumber measurement units. Actual lumber measurements and pricing may vary by supplier and region. Always confirm dimensions and pricing units with your supplier before making purchases. Measurements shown use nominal dimensions unless otherwise specified.