Square Feet vs. Linear Feet

The core difference

Square feet measure area. Two dimensions, multiplied. A 10 × 10 ft room is 100 square feet, and that number tells you how much surface you have to cover.

Linear feet measure length. One dimension. Ten linear feet is ten feet along the material, whether that material is 3 inches wide or 3 feet wide.

They answer different questions. Square feet answer “how much surface?”; linear feet answer “how long a run?”.

Why you cannot convert without the width

This is the part that catches people. Asking “how many linear feet in 100 square feet?” is like asking how many pages are in a pound of paper — the question is incomplete until you know something about the material.

The same 100 linear feet covers:

• 25 square feet if the material is 3 inches wide
• 50 square feet at 6 inches wide
• 100 square feet at 12 inches wide
• 200 square feet at 24 inches wide

The width is what connects them.

The conversion formula

Linear feet = Square feet ÷ (Width in inches ÷ 12)

Worked through for 320 sq ft of 8-inch-wide hardwood:

1. Convert the width to feet: 8 ÷ 12 = 0.667 ft
2. Divide: 320 ÷ 0.667 = 480 linear feet

Reverse it by multiplying: 480 × 0.667 = 320 sq ft.

The sqft to linear feet calculator runs this both ways.

Reference table

Linear feet needed to cover 100 square feet:

Material width	Width in feet	Linear feet for 100 sq ft
2.25 in	0.188 ft	533 linear ft
3 in	0.25 ft	400 linear ft
4 in	0.333 ft	300 linear ft
5 in	0.417 ft	240 linear ft
6 in	0.5 ft	200 linear ft
7.5 in	0.625 ft	160 linear ft
12 in	1 ft	100 linear ft
24 in	2 ft	50 linear ft

Note the 12-inch row: when material is exactly one foot wide, square feet and linear feet are numerically identical. That coincidence is probably responsible for a good share of the confusion.

Where each unit is used

Sold by the linear foot

• Hardwood, laminate and engineered flooring planks
• Trim, baseboard, crown moulding and casing
• Lumber — a 2×4 is priced per linear foot
• Countertops
• Fencing and railing
• Fabric, carpet and vinyl off a roll
• Gutters and downspouts

Sold by the square foot

• Tile
• Carpet, in some markets
• Sheet goods such as plywood and drywall
• Roofing, usually in “squares” of 100 sq ft
• Paint coverage
• Property and land

Where it matters in practice

Comparing quotes. One supplier quotes $4.50 per square foot, another $2.80 per linear foot for 6-inch planks. The second is $2.80 ÷ 0.5 = $5.60 per square foot — considerably more expensive, despite looking cheaper.

Trim and baseboard. These are pure linear feet. You need the room perimeter, not the area. A 14 × 12 ft room needs 52 linear feet of baseboard, less the door openings — the floor’s 168 square feet is irrelevant.

Countertops. Usually quoted per linear foot of run, though some fabricators price per square foot. Ask which, because a deep island changes the two figures very differently.

Fencing. Linear feet of the perimeter. The area enclosed does not affect the material at all.

Do not forget waste

Whichever unit you order in, add an allowance:

• 10% for straightforward straight-lay installations
• 15% for diagonal or herringbone layouts, and rooms with many corners

For 480 linear feet of hardwood at 10%, order 528 linear feet. Buy it all in one order — flooring is made in dye lots and a later top-up can be a visibly different shade. The flooring guide covers this in more detail.