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How to Calculate Linear Feet: Formula, Examples & Common Uses

Learn how to calculate linear feet for fencing, flooring, trim, and other materials sold by the linear foot. Covers the difference between linear feet, square feet, and board feet.

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What Is a Linear Foot?

A linear foot is simply a length measurement of one foot. Unlike square feet (which measures area in two dimensions), linear feet measures only length in one dimension. Width and height are not part of the measurement.

Materials sold by the linear foot: fencing, lumber (railing, trim, baseboard), pipe, conduit, chain, fabric by the yard/foot.

Basic Linear Feet Calculation

Total Linear Feet = Sum of all lengths being measured (in feet)

Example — Fence: A yard with 4 sides: - Side A: 45 ft - Side B: 30 ft - Side C: 45 ft - Side D: 30 ft - Total: 150 linear feet of fencing needed

Example — Baseboard: A room measuring 14×12 ft with one 3-ft door opening: - Perimeter: 2 × (14 + 12) = 52 ft - Subtract door: −3 ft - Add 10% waste for cuts at corners - Total: 49 × 1.10 = 53.9 → order 54 linear feet

Converting Between Linear Feet and Square Feet

You cannot convert between linear feet and square feet without knowing the width of the material.

Area (sq ft) = Linear Feet × Width (ft) Linear Feet = Area (sq ft) ÷ Width (ft)

Example — Flooring: 250 sq ft room, flooring planks are 5 inches wide: - Linear feet needed: 250 ÷ (5/12) = 250 ÷ 0.417 = 599 linear feet of planking

Example — 6-inch fence boards: 120 linear feet of fence, 6-inch wide boards: - Total board coverage: 120 linear ft - Each 6-ft board covers 6 ft of length - Boards needed: 120 ÷ 1 = 120 boards (each board covers 1 linear foot of fence at 6-inch width)

Board Feet vs. Linear Feet

Board feet is a volume measurement used for lumber: Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12

A 2×4×8 stud: (2 × 4 × 8) ÷ 12 = 5.33 board feet A 2×6×8 stud: (2 × 6 × 8) ÷ 12 = 8 board feet

Linear feet measures the length only; board feet accounts for both cross-section dimensions. Framing lumber is usually priced per linear foot (for standard dimensions) or per board foot (for custom or dimensional lumber).

Waste Factors for Common Applications

MaterialWaste Factor
Baseboard / trim10% (45° miter cuts)
Tongue-and-groove flooring10–15%
Fencing5%
Crown molding15–20% (complex inside corners)
Chair rail / picture rail10%

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Frequently Asked Questions

What is the difference between linear feet and square feet?
Linear feet measures length only (one dimension). Square feet measures area (two dimensions: length × width). A 20-foot board is 20 linear feet. A 20×15 ft room is 300 square feet. You need to know the width to convert between them.
How do I calculate linear feet for baseboard?
Measure the perimeter of all walls that need baseboard. Subtract doorway widths (typically 3 ft each). Add 10% for miter cuts and waste. Example: 12×14 ft room with one door: (2×12 + 2×14) − 3 = 49 ft × 1.10 = 54 linear feet needed.
How many linear feet are in a square foot?
You cannot directly convert — linear feet and square feet measure different things. One linear foot of material that is 12 inches wide equals 1 square foot. One linear foot of material 6 inches wide equals 0.5 square feet. The width of the material is the missing factor.
How do I calculate linear feet for fencing?
Measure the perimeter of the area to be fenced. Subtract any gaps for gates. Add 5% for waste. Example: A 100×60 ft yard: perimeter = 2×(100+60) = 320 ft. Subtract two 4-ft gate openings = 312 ft × 1.05 = 328 linear feet of fence panels needed.

Last updated 7/28/2026