What is the difference between board feet and square feet?

Board feet measures volume (3D: length × width × thickness). Square feet measures area (2D: length × width). Board feet is used for lumber; square feet is used for surfaces like flooring.

What is the difference between board feet and linear feet?

Board feet measures volume (3D). Linear feet measures length only (1D). To convert between them, you need the board’s width and thickness. Use our board foot calculator (https://board-foot-calculator.org/) for quick conversions.

When should I use board feet instead of square feet?

Use board feet when buying solid lumber where thickness affects pricing (hardwood is commonly priced by volume). Use square feet for flooring and other surface measurements.

How do I convert board feet to square feet?

Divide board feet by thickness (in inches). Example: 10 BF of 1" lumber = 10 SF. Try the BF to Square Feet converter (https://board-foot-calculator.org/tools/board-feet-to-square-feet-calculator).

How do I convert board feet to linear feet?

You need both thickness and width. Use: LF = BF × 12 ÷ (T × W). Try the BF to Linear Feet converter (https://board-foot-calculator.org/tools/board-feet-to-linear-feet-calculator).

Why does lumber use board feet instead of square feet?

Because solid lumber comes in many thicknesses (1", 2", 4/4, 8/4). Board feet includes thickness, so pricing stays consistent when boards are thicker or thinner.

What’s an example of when to use each unit?

Linear feet: fence boards or trim. Square feet: flooring or paint coverage. Board feet: buying hardwood for a woodworking project.

Can I use square feet to buy lumber?

For sheet goods (plywood, MDF) sold by area, yes. For solid hardwood lumber, board feet is the industry standard.

Board Feet vs Square Feet vs Linear Feet: What's the Difference?

Last Updated: 2025-12-28

Learn the difference between board feet, square feet, and linear feet. Quick comparison table, conversion formulas, and when to use each unit for lumber.

These three units measure lumber differently. Here is the fast way to tell them apart.

Quick comparison of linear feet (length), square feet (area), and board feet (volume).
Unit	Measures	Dimension	Common uses
1D Linear Foot (LF)	Length	1D	Trim, fence boards, pipe, baseboards
2D Square Foot (SF)	Area	2D	Flooring, paint coverage, tile, sheet goods
3D Board Foot (BF)	Volume	3D	Hardwood lumber pricing, woodworking projects, logs

Board Foot Calculator BF to Square Feet BF to Linear Feet

Definitions (what each unit measures)

Think in dimensions: 1D is length, 2D is area, 3D is volume.

Linear feet measures length. Square feet measures area. Board feet measures volume.

Linear Foot (LF)

Measures length only. Example: 8 linear feet of trim means the trim is 8 feet long.

Square Foot (SF)

Measures area. Formula: SF = L × W (in feet). Example: 8 ft × 4 ft = 32 SF.

Board Foot (BF)

Measures lumber volume. 1 board foot is 12" × 12" × 1" = 144 cubic inches. A common formula is BF = (T(in) × W(in) × L(ft)) ÷ 12.

When to use each unit

Examples of when to use linear feet, square feet, and board feet.
Unit	Use it for	Typical examples
Linear feet (LF)	Length-based purchasing	Fence boards, trim, pipe, baseboards
Square feet (SF)	Surface coverage	Flooring, wall paint, tile, sheet goods
Board feet (BF)	Solid lumber volume (thickness matters)	Hardwood pricing, woodworking projects, logs

Conversions (what extra info you need)

To convert to or from board feet, you usually need one extra dimension: thickness (and sometimes width).

Conversion formulas between board feet, square feet, and linear feet.
Conversion	Formula	You need	Example
BF → SF	SF = BF ÷ Thickness(in)	Thickness (in)	10 BF of 1" lumber = 10 SF
SF → BF	BF = SF × Thickness(in)	Thickness (in)	10 SF of 2" lumber = 20 BF
BF → LF	LF = BF × 12 ÷ (Thickness(in) × Width(in))	Thickness + Width (in)	10 BF of 1"×6" = 20 LF
LF → BF	BF = LF × Thickness(in) × Width(in) ÷ 12	Thickness + Width (in)	20 LF of 1"×6" = 10 BF

Use our free converters → Board foot formula guide

Common mistakes

Mixing square feet and board feet (thickness changes the result)
Forgetting thickness when converting BF ↔ SF
Forgetting width and thickness when converting BF ↔ LF
Using nominal sizes (like “2×4”) instead of actual measurements

Summary table

Summary comparison of linear feet, square feet, and board feet, including how to convert to board feet.
Unit	Definition	Dimension	Typical uses	Convert to BF
Linear Foot (LF)	Length only	1D	Fence, trim, pipe	BF = LF × T × W ÷ 12
Square Foot (SF)	Area (L × W)	2D	Flooring, coverage	BF = SF × Thickness(in)
Board Foot (BF)	Volume (T × W × L)	3D	Lumber pricing, projects	—