Circle Calculator

Computes area, circumference, diameter, and radius of a circle

Input Options
Circle Visualization
Results
Circle Properties

The radius of a circle is the distance from the center to any point on the circle's edge. It's half the length of the diameter.

The diameter of a circle is a straight line passing through the center and connecting two points on the circle. It equals twice the radius.

The circumference is the distance around the circle. It equals 2πr or πd, where r is the radius and d is the diameter.

The area of a circle is the space contained within the circumference. It's calculated using the formula A = πr².

A chord is a line segment whose endpoints lie on the circle. The diameter is the longest chord of a circle.

An arc is a portion of the circumference of a circle. The length of an arc depends on the central angle it subtends.

A sector is a region of a circle enclosed by two radii and an arc. The area of a sector is proportional to the central angle.

A tangent is a line that touches the circle at exactly one point. It is perpendicular to the radius at the point of tangency.