Linear Foot to Square Foot Calculator

Linear feet vs square feet — what's the difference?

These two measurements are often confused because they both use feet, but they measure completely different things. A linear foot measures length — one dimension. A square foot measures area — two dimensions multiplied together. You cannot convert between them without knowing the width of the material or space you're measuring.

Think of it this way: if you unroll a bolt of fabric onto the floor, the length of fabric from the roll to your cutting point is measured in linear feet. The area of fabric you can cover on the floor is measured in square feet. A 10-foot piece of 60-inch-wide fabric covers 10 × 5 = 50 square feet, while a 10-foot piece of 36-inch-wide fabric covers only 10 × 3 = 30 square feet.

This distinction matters practically when you're buying materials like flooring, fencing, trim, siding, or lumber. Always identify whether the price is per linear foot or per square foot, and make sure you're comparing correctly.

Formula and examples

Worked examples

Common uses for this conversion

Hardwood flooring. Hardwood planks are often sold by linear foot at a specific width (e.g., 3-inch, 4-inch, 5-inch). To cover a room, calculate the room's square footage, then convert to linear feet based on plank width. Add 10–15% for cutting waste.

Fencing. Privacy fence boards are often sold by the piece in linear feet. To estimate material for a fence of a given height, calculate the perimeter in linear feet, then account for board width to find how many boards you need.

Lumber and trim. Crown molding, baseboards, and similar trim pieces are sold in linear feet. A room perimeter of 60 linear feet of baseboard times the material width gives the total coverage area — useful for comparing material costs.

Fabric and textiles. Fabric is sold in linear yards or linear feet at a standard bolt width (usually 44 or 60 inches). Converting to square feet helps you compare fabric amounts across different widths.

Frequently asked questions

• What is the difference between a linear foot and a square foot?
  A linear foot is a one-dimensional measurement of length — it measures how long something is. A square foot is a two-dimensional measurement of area — it measures the surface covered by a space one foot wide and one foot long. To convert linear feet to square feet, you must know the width of the material or space. Square feet = Linear feet × Width (in feet).
• How do I convert linear feet to square feet?
  Multiply the number of linear feet by the width of the material in feet. For example, 20 linear feet of flooring that is 6 inches (0.5 feet) wide equals 20 × 0.5 = 10 square feet. If the width is given in inches, divide by 12 first to convert to feet before multiplying.
• How many square feet are in a linear foot of 12-inch wide material?
  If material is 12 inches (1 foot) wide, then 1 linear foot equals exactly 1 square foot. This is because 1 LF × 1 ft width = 1 SF. For wider or narrower material, the ratio changes proportionally.
• Why do lumber and flooring sometimes use linear feet instead of square feet?
  Linear feet describe the length of a board or strip without specifying how wide it is. This is useful when selling material by the running length — for example, crown molding, baseboard trim, fencing rails, or lumber planks of a standard width. When you need to cover an area, you must know the material width to calculate how many linear feet you need.
• How do I calculate linear feet of flooring needed for a room?
  First calculate the room area in square feet (length × width). Then divide by the width of each flooring plank in feet. For example, a 12×15 ft room (180 sq ft) with 4-inch wide planks (0.333 ft) requires 180 ÷ 0.333 = 540 linear feet of flooring. Add 10–15% for waste and cuts.
• How do I convert square feet back to linear feet?
  Divide square feet by the material width in feet. If you have 150 square feet and the material is 18 inches (1.5 feet) wide, you need 150 ÷ 1.5 = 100 linear feet. This is covered by the second tab of this calculator.
• What is a board foot and how is it different?
  A board foot (BF) is a volume measurement used for lumber, equal to a board 1 foot × 1 foot × 1 inch thick. It is different from both linear feet and square feet. Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For finished lumber sold by linear foot, the width is usually specified separately.
• How much waste should I add to my linear foot calculation?
  For most flooring projects, add 10% waste for a simple rectangular room. For rooms with diagonal cuts, patterns, or many obstacles, add 15–20%. For tile work or irregular shapes, 15% is a common starting point. For trim and molding, add 15% for corners and waste cuts.