12 FOCUSED TOOLS
Circle & ellipse calculators
Calculate curved areas, arcs, chords and circular borders.
Choose the right calculation
Distinguish radius from diameter before entering measurements. Arc length follows the curve, while chord length runs straight between endpoints. Ring-shaped areas subtract the inner circle from the outer one.
Find a tool for your question
Circle Area Calculator
Calculate the area enclosed by a circle from its radius.
Circle Circumference Calculator
Find the distance around a circle using its radius.
Ellipse Area Calculator
Calculate the enclosed area of an ellipse using its two semi-axes.
Sector Area Calculator
Calculate a circular sector’s area from radius and angle in degrees.
Arc Length Calculator
Find the length of a circular arc from radius and central angle.
Annulus Area Calculator
Find the area of a ring between two concentric circles.
Circle Segment Area Calculator
Calculate the smaller circular segment cut off by a chord.
Chord Length Calculator
Find the straight chord connecting two points on a circle.
Circle Radius From Area Calculator
Recover a circle’s radius from its enclosed area.
Circle Radius From Circumference Calculator
Recover a circle’s radius from its circumference.
Ellipse Perimeter Calculator
Estimate the circumference of an ellipse from its semi-axes.
Circular Sector Perimeter Calculator
Find the boundary length of a sector bounded by an arc and two radii.
How is chord length different from arc length?
A chord is a straight line between two points on the circle. An arc follows the circular boundary between those points.
Useful next steps in other categories
Cylindrical Tank Capacity Calculator
Calculate liquid volume in a vertical cylinder at a chosen water depth.
Mulch Volume Calculator
Estimate mulch volume for a circular planting bed excluding a central unmulched area.
More geometry topics
Triangle
Find triangle sides, areas and perimeter from different known measurements.
Explore topic ↗17 calculatorsQuadrilateral & polygon
Measure areas and outlines of rectangles, kites and regular polygons.
Explore topic ↗29 calculatorsVolume & surface area
Find capacity and outside area for common three-dimensional shapes.
Explore topic ↗8 calculatorsCoordinate & vector
Calculate distances and vector relationships in two or three dimensions.
Explore topic ↗