Circle Calculator

A circle is a perfectly round shape where all points on the edge are the same distance from the center point. This distance is called the radius (r). The circle is one of the most fundamental shapes in geometry and has many important properties and applications.

The key properties of a circle include its radius (r), diameter (d), circumference (C), and area (A). These properties are all related by simple mathematical formulas.

The following formulas define the relationships between the different properties of a circle:

Choose the circle measurement you already know, enter the value, and let the calculator derive the remaining properties automatically.

1. Select which circle property you know (radius, diameter, circumference, or area).
2. Enter the value for that property.
3. Click the 'Calculate' button.
4. View the calculated values for all other properties along with the step-by-step calculation.

Tip: use the same unit for interpretation across all results, because the calculator keeps every output in the same measurement system as the input.

Circle calculations have numerous practical applications in various fields:

• Engineering: Designing circular components, pipes, wheels, and gears.
• Architecture: Planning circular structures and spaces.
• Physics: Analyzing rotational motion and orbital paths.
• Everyday life: Calculating areas of circular objects, such as pizza sizes, round tables, or garden plots.