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Circle Segment Area Calculator
Calculate the area of a circular segment, the region between a chord and the arc it cuts off, from the radius and central angle.
cm
degrees
What this calculator finds
A circular segment is the region enclosed between a chord and the arc that connects the same two points. This calculator finds the segment’s area, along with the related sector area and chord length.
The formula
Segment area is found by subtracting the triangle formed by the two radii and chord from the full pie-slice sector: A = ½r²(θ – sinθ), where r is the radius and θ is the central angle in radians (degrees are converted automatically).
This is useful in geometry, engineering, and design work involving partial circles, such as arched windows or tank fill levels. This tool is for general educational and planning purposes.
Last reviewed August 2026