Square Feet to Linear Feet Calculator

Frequently Asked Questions

What is the formula to convert square feet to linear feet?

Linear feet = square feet × 12 ÷ width in inches. For example, 100 sq ft of 6-inch-wide boards = 100 × 12 ÷ 6 = 200 linear feet. The width of your material is the key input — without it, square feet cannot be converted to linear feet.

What is a linear foot?

A linear foot is simply 12 inches measured in a straight line, regardless of width. Lumber, trim, piping, and fencing are sold by the linear foot because you care about length, not area. Square feet measure area (length × width); linear feet measure length only.

Why does the material width matter?

Because the same area needs more length when boards are narrow. Covering 100 sq ft with 4-inch boards takes 300 linear feet, but with 12-inch boards it takes only 100 linear feet. Always use the actual face width of the material you are buying — for a nominal 2×4, that is 3.5 inches, not 4.

What are common lumber widths to enter?

Use the actual (not nominal) widths: 2×4 = 3.5", 2×6 = 5.5", 2×8 = 7.25", 1×6 = 5.5", deck boards = 5.5", plywood sheets = 48". The calculator has quick-pick buttons for these common widths.

How do I convert linear feet back to square feet?

Use the second tab: square feet = linear feet × width in inches ÷ 12. For example, 200 linear feet of 6-inch boards = 200 × 6 ÷ 12 = 100 sq ft.

Is this linear feet calculator free?

Yes — completely free, no signup, no limits. It runs 100% in your browser, so your numbers never leave your device.