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Square Footage Calculator

Calculate the area of any rectangular space in square feet, square meters, and square yards.

Quick answer

220 sq ft (24.4 sq yd / 20.4 m²). Two rectangles beat one wrong rectangle.

Calculator

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How it works

Length × Width = Area

For imperial inputs, length and width are in feet. Multiplying them gives the area in square feet — the most common unit for measuring floor space in the US.

Square feet ÷ 9 = Square yards

One square yard equals 9 square feet (3 ft × 3 ft). Dividing by 9 converts the area to square yards, which is useful for ordering carpet and other flooring materials.

Square feet × 0.092903 = Square meters

Multiplying by 0.092903 converts square feet to square meters — the standard area unit in the metric system.

Worked example

A room that is 15 ft × 12 ft:

15 × 12 = 180 sq ft

180 ÷ 9 = 20 sq yd

180 × 0.092903 = 16.72 m²

The room is approximately 180 square feet.

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Every estimate downstream — concrete, paint, flooring, sod — is only as accurate as the square footage feeding it. And the errors are always the same three: mixing feet and inches mid-measurement, treating an L-shaped room as one big rectangle, and forgetting to subtract the parts you don't cover.

This calculator multiplies length by width and converts to square meters and square yards in one step. For L-shaped or irregular spaces, split them into rectangles, run each through the calculator, and add the results.

How to measure square footage

  1. Pick one unit and stick to it for the whole project — convert inches to decimal feet (6 in = 0.5 ft) before you multiply.
  2. Measure wall to wall at the longest and widest points. For L-shapes, split into two rectangles and add them.
  3. Subtract what you don't cover: fireplaces, built-ins, and stair openings all come out of the total.
  4. Use the conversions directly: ÷ 9 for square yards (carpet, concrete), × 0.0929 for square meters.

Area conversions & formulas

ConversionFactor
Square feet → square yards÷ 9
Square feet → square meters× 0.0929
Square feet → acres÷ 43,560
Square inches → square feet÷ 144
Circleπ × r²
Triangle½ × base × height

1 m² = 10.7639 ft²; 1 acre = 43,560 ft².

Worked example: L-shaped room

A room that's 20 × 15 ft overall with a 10 × 8 ft section missing (an L-shape):

  1. Full rectangle: 20 × 15 = 300 sq ft.
  2. Missing section: 10 × 8 = 80 sq ft.
  3. Actual area: 300 − 80 = 220 sq ft.
  4. To square yards: 220 ÷ 9 = 24.4 sq yd.
  5. To square meters: 220 × 0.0929 = 20.4 m².

220 sq ft (24.4 sq yd / 20.4 m²). Two rectangles beat one wrong rectangle.

Pro tips for measuring area

  • Measure twice, in the same unit. The most common error in the trade isn't bad math — it's a 10-foot wall recorded as 10 inches.
  • Photograph the tape measure at each wall. When the material takeoff looks wrong a week later, the photo settles it.
  • Round up the materials you buy, never the measurement itself. Padding the measurement hides real errors.
  • For flooring and tile, measure the room — then measure again after the underlayment or backer board goes in, if it changes dimensions.

How to use the square footage calculator

1. Choose your unit system — Imperial (feet) or Metric (meters).

2. Enter the length of your area.

3. Enter the width of your area.

4. Click Calculate to see your results in square feet, square meters, and square yards.

How square footage is calculated

Area is calculated by multiplying the length by the width of your space. This gives you the total surface area in the unit system you selected.

In the imperial system, the result is in square feet. The calculator also converts to square yards by dividing by 9, and to square meters by multiplying by 0.092903.

In the metric system, the result is in square meters. The calculator converts to square feet and square yards automatically.

Why calculate square footage?

Square footage is one of the most common measurements used in home improvement, real estate, and construction. Knowing the area of a space helps you estimate how much material you need — whether that is paint, flooring, tile, sod, or concrete.

It is also useful for comparing property sizes, calculating rental rates, and planning room layouts.

Square footage calculator example

Let's say you're measuring a room that is 15 feet long and 12 feet wide.

Calculate the area: 15 × 12 = 180 square feet.

Convert to square yards: 180 ÷ 9 = 20 square yards.

Convert to square meters: 180 × 0.092903 = 16.72 square meters.

Your room is approximately 180 square feet, 20 square yards, or 16.72 square meters.

Frequently Asked Questions

How do I calculate square footage?+
Multiply the length by the width of your area. Make sure both dimensions use the same unit. For example, a room that is 12 feet long and 10 feet wide has an area of 120 square feet.
How do I convert square feet to square meters?+
Multiply the area in square feet by 0.092903. For example, 100 square feet equals approximately 9.29 square meters. The calculator handles this conversion automatically.
How do I convert square feet to square yards?+
Divide the area in square feet by 9. One square yard equals 3 feet × 3 feet, or 9 square feet. For example, 180 square feet equals 20 square yards.
How do I measure an irregularly shaped area?+
Break the area into smaller rectangles, calculate the square footage of each one, and add the results together. For triangular sections, multiply the base by the height and divide by 2.
Why do I need to calculate square footage?+
Square footage is essential for estimating materials like paint, flooring, tile, sod, and concrete. It is also used for real estate listings, rental agreements, and property tax assessments.

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