Circle Calculator
Enter any value — radius, diameter, circumference, or area — and calculate all other properties instantly.
cm
Enter the radius value.
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Area
0 cm²
πr² = π × 0² = 0 cm²
Radius
r
0 cm
Diameter
d = 2r
0 cm
Circumference
C = 2πr
0 cm
Documentation
Understanding Circles
A circle is a perfectly round shape where every point on its edge is exactly the same distance from the center. This distance is called the radius.
Diameter
Circumference
Area
Tip: Remember "Circumference = π × Diameter" as "Pi times across = around".
Frequently Asked Questions
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