Circle Square Footage Calculator

Square Footage of a Circle

Square footage of a circle is the area of a circular region expressed in square feet (sq ft or ft²). It is essential for flooring, landscaping, pool design, and any project where you need to estimate materials for a round surface. Use our calculator with radius or diameter in feet, inches, yards, meters, or centimeters.

Formula

$$SF = \pi r^2 = \frac{\pi d^2}{4}$$

where $r$ is the radius and $d$ is the diameter, both in feet.

Worked Example

A circular patio has a diameter of 16 ft. The square footage is $\pi \times 8^2 = 201.06$ sq ft.

Frequently Asked Questions

How do I calculate the square footage of a half-circle?

Divide the full circle area by 2. If the radius is $r$, then $SF_{half} = \pi r^2 / 2$.

What is the square footage of a 16-foot diameter circle?

About 201.06 sq ft. Use $SF = \pi d^2 / 4$ with $d = 16$ ft.

Can I enter the radius in centimeters?

Yes. The calculator converts your input to feet before applying the area formula.

How is square footage different from circumference?

Square footage measures area in square units. Circumference measures the distance around the circle in linear units.

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Square Footage Circle Calculator

Square Footage of a Circle

Formula

Worked Example

Frequently Asked Questions

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