Calculate circle area, circumference, radius, diameter, arc length, and sector area with this free circle calculator.
Area:
A = πr²
Circumference:
C = 2πr or πd
Arc length:
L = (θ/360) × 2πr
Sector area:
A = (θ/360) × πr²
Circle measurements are used in geometry, design, engineering, construction, landscaping, and many everyday sizing problems.
Understanding radius, diameter, area, and circumference helps with layout and measurement tasks.
Your result shows the selected circle value along with supporting measurements such as radius, diameter, area, circumference, arc length, or sector area.
This makes it easier to understand how one circle measurement connects to the others.
The radius goes from the center to the edge, while the diameter goes all the way across the circle through the center.
Circumference is the distance around a circle.
Arc length is the distance along part of a circle's edge based on the central angle.
A sector is a slice of a circle formed by two radii and the arc between them.