Math

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Square Footage Circle Calculator.

Calculate circular area from radius.

On-device calculationNo signup
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Set your values

Results update as you type.

Result: squareFeet: 78.53981634

Result

squareFeet: 78.53981634

Use Cases

Home Improvement Projects

Determine the amount of material needed for circular areas like garden beds, patios, or rugs. Enter the radius to get the square footage for purchasing flooring, gravel, or turf.

Example: A circular patio with a radius of 8 feet has an area of about 201.06 sq ft.

Landscaping and Gardening

Plan circular flower beds, ponds, or fire pits. Calculate the area to estimate soil, mulch, or liner requirements.

Example: For a circular pond with a radius of 3 feet, the area is about 28.27 sq ft.

Frequently Asked Questions

How do I calculate the square footage of a circle?
Enter the radius of the circle in feet into the calculator. The calculator uses the formula πr² to compute the area in square feet. For example, a circle with a radius of 5 feet has an area of approximately 78.54 square feet.
What is the formula for circle area?
The formula is Area = π × radius². Here, π (pi) is approximately 3.14159, and the radius is the distance from the center to the edge. The result is in square feet if the radius is in feet.
Can I use this calculator for a half-circle or quarter-circle?
This calculator computes the area of a full circle. For a half-circle, divide the result by 2; for a quarter-circle, divide by 4. Ensure you enter the radius of the full circle.

Tips & Common Mistakes

Tips

  • Measure the radius accurately: the radius is half the diameter. If you have the diameter, divide it by 2 before entering.
  • Ensure the radius is in feet to get square feet. If you measure in inches, convert to feet by dividing by 12.
  • For irregular shapes, break them into circles and other shapes, then sum the areas.
  • Double-check your input: a small error in radius can significantly affect the area because it is squared.

Common Mistakes to Avoid

  • Entering the diameter instead of the radius. The radius is half the diameter.
  • Using inches without converting to feet, resulting in square inches instead of square feet.
  • Forgetting to square the radius in manual calculations, leading to an area that is too small.

Last updated: August 13, 2026