Circle Solver
Given any ONE of radius, diameter, circumference, or area, compute the other three. Works in any consistent length unit (meters, feet, inches, etc.). Includes an interactive draggable visualizer.
Drag the open circle to resize. The drag updates whichever input is your active "starting point" (set above). Press Calculate for the final result.
Limitations: No unit conversion is performed. Feed consistent units (e.g., if radius is in meters, area will be in m²). The "unit" field is a label only.
What to do next: To solve for the radius of a circular pool holding 50 m² of surface area, pick "I know the area", enter 50, and read the radius from the output.