Square Footage

Area of a rectangular space — enter in any length unit.

Area

11.15
120 ft²

How to Calculate Square Footage

  1. Measure the length of the room or area using a tape measure and record it in feet. If your measurement is in inches, divide by 12 to convert to feet.
  2. Measure the width of the room or area and record it in feet using the same conversion if needed.
  3. Multiply the length by the width: Area = Length × Width. The result is your square footage.
  4. For irregularly shaped rooms, divide the space into multiple rectangles (or other shapes), calculate each area separately, then add all the areas together.
  5. Add 10–15% to your final square footage when purchasing materials like flooring or tile to account for cuts, waste, and overlap.

Square Footage Formula

Area (ft²) = Length (ft) × Width (ft)

For a rectangle or square room, square footage is simply the product of its length and width. Both measurements must be in feet before multiplying. If your measurements are in inches, divide each by 12 first. If in yards, multiply each by 3. The result is the area in square feet (ft²).

For other shapes:

  • Triangle: Area = (Base × Height) / 2
  • Circle: Area = π × Radius²
  • L-shaped room: Split into two rectangles, calculate each area separately, then add them together.
  • Area (ft²) — The resulting square footage of the space, expressed in square feet.
  • Length (ft) — The longer dimension of the rectangular space, measured in feet.
  • Width (ft) — The shorter dimension of the rectangular space, measured in feet.

Worked Example: Calculating the Square Footage of a Bedroom

Length = 14 feet, Width = 12 feet
Area = 14 ft × 12 ft = 168 ft²

Result: 168 square feet

What Your Result Means

A room that is 14 feet long and 12 feet wide has a total area of 168 square feet. If you were purchasing hardwood flooring at $4.50 per square foot, you would need approximately 168 ft², costing around $756 before adding the recommended 10% waste buffer (which would bring the total to about 185 ft² and ~$832).

Understanding Square Footage

Understanding Square Footage

Square footage (ft²) is one of the most commonly used measurements in real estate, construction, and home improvement. It describes the total two-dimensional area of a surface or room.

Common Uses

  • Real estate listings: Home sizes are advertised in square feet. A typical U.S. single-family home averages around 2,300 sq ft.
  • Flooring and carpet: Sold by the square foot or square yard (1 sq yd = 9 sq ft).
  • Painting: A gallon of interior paint typically covers 350–400 sq ft per coat.
  • Landscaping and sod: Sold and priced per square foot.
  • HVAC sizing: Air conditioning and heating systems are sized based on the square footage of the area they need to condition.

Unit Conversions

| From | To Square Feet | Multiply By | |------|---------------|-------------| | Square inches | Square feet | ÷ 144 | | Square yards | Square feet | × 9 | | Square meters | Square feet | × 10.764 | | Acres | Square feet | × 43,560 |

Measuring Irregular Rooms

For L-shaped, T-shaped, or other complex rooms:

  1. Sketch the floor plan on paper.
  2. Divide the shape into simple rectangles or triangles.
  3. Calculate each section's area individually.
  4. Sum all sections for the total square footage.

Why Add Extra Material?

When purchasing flooring, tile, or carpet, industry professionals recommend adding 10% for standard rooms and 15% for rooms with diagonal cuts or complex layouts to account for waste from cutting and fitting.

Common Mistakes

  • Forgetting to convert measurements to the same unit (feet) before multiplying — mixing feet and inches will give a wildly incorrect result.
  • Not accounting for waste when ordering materials; always add at least 10% to the calculated square footage for flooring and tile projects.
  • Measuring only one large rectangle in an L-shaped room instead of dividing it into sections, which overstates the actual area.
  • Confusing square feet with linear feet — linear feet measure length in one dimension, while square feet measure area in two dimensions.
  • Using outside wall measurements for interior square footage — always measure inside walls for flooring, and outside dimensions for roofing or exterior projects.

Common Questions About Square Footage

What is the square footage of an average American home?

According to the U.S. Census Bureau, the median size of a newly built single-family home in the United States is approximately 2,299 square feet as of recent data, though existing homes average somewhat smaller.

How do I calculate square footage for a circular area?

Use the formula: Area = π × r², where r is the radius (half the diameter). For example, a circular patio with a 10-foot diameter has a radius of 5 ft, so Area = 3.14159 × 5² ≈ 78.5 sq ft.

How much does square footage affect home value?

Square footage is one of the primary drivers of home value. Real estate appraisers use a price-per-square-foot metric to compare similar homes. In most U.S. markets, every additional 100 square feet can add thousands of dollars to a home's appraised value, depending on location and condition.

How do I calculate the square footage of a triangular area?

Use the formula: Area = (Base × Height) / 2. For a triangular garden plot with a base of 20 feet and a height of 15 feet, the area = (20 × 15) / 2 = 150 sq ft.

Frequently Asked Questions

How do I convert inches to square feet?

First convert each measurement from inches to feet by dividing by 12. Then multiply: Area (ft²) = (Length in inches ÷ 12) × (Width in inches ÷ 12). For example, a surface that is 60 inches × 48 inches = 5 ft × 4 ft = 20 sq ft.

How many square feet are in a 10×10 room?

A 10-foot by 10-foot room is exactly 100 square feet (10 × 10 = 100 ft²).

How do I calculate square footage of an L-shaped room?

Divide the L-shape into two rectangles. Measure and calculate the area of each rectangle separately, then add them together. For example, if one section is 10×8 ft (80 ft²) and the other is 6×5 ft (30 ft²), the total is 110 ft².

How many square feet are in a square yard?

There are 9 square feet in 1 square yard. To convert square yards to square feet, multiply by 9. To convert square feet to square yards, divide by 9.

How do I calculate square footage for flooring?

Measure the length and width of each room, calculate the square footage, add all rooms together, then add 10% for waste and cutting. This gives you the total amount of flooring material to purchase.

Related Calculators

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