✓ Effortless Math · Free Tool

Arc Length & Sector Area Calculator

Enter a circle's radius and a central angle to get the arc length, the sector area, the chord, and the sector perimeter — with a labeled diagram and step-by-step working.

Arc length:  s = rθ  ·  Sector area:  A = ½r²θ  (θ in radians)
radius r angle θ °

Enter the radius and the central angle. Arc length uses s = rθ (θ in radians).

Results

Arc length & sector area
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Arc length (s = rθ)
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Sector area (½r²θ)
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Chord length
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Sector perimeter (2r + s)
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Angle in radians
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Fraction of circle
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Full circumference
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Full circle area
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Sector diagram

CircleSectorArc

Step-by-step