Area of a Sector Calculator

Use this calculator to easily calculate the area of a sector given its radius and angle.

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Area of a sector formula

The formula for the area of a sector is (angle / 360) x height x π x radius2. The figure below illustrates the measurement:

area sector

As you can easily see, it is quite similar to that of a circle, but modified to account for the fact that a sector is just a part of a circle. Measuring the diameter is easier in many practical situations, so another convenient way to write the formula is (angle / 360) x height x π x (diameter / 2)2. The radius can be expressed as either degrees or radians, with our area of a sector calculator accepting only degrees for now (let us know if it would help you if it supported radians as well). π is, of course, the mathematical constant equal to about 3.14159.

Area of a Sector calculation

You need to measure or know to things: the sector's radius and its angle. If the sector is a quadrant, then the angle is 90°. There are different tools for measuring angles, depending on your particular situation. A protractor can be useful in many cases.

After you have obtained the measurements, just apply the formula above or use our sector calculator as an easier and faster alternative.

Cite this calculator & page

If you'd like to cite this online calculator resource and information as provided on the page, you can use the following citation:
Georgiev G.Z., "Area of a Sector Calculator", [online] Available at: URL [Accessed Date: 21 Jan, 2019].