Method
D = 2r, C = 2πr and A = πr². Arc and sector measures multiply the full-circle quantity by θ/360.
Math worksheet
Circle Calculator
Start with radius, diameter, circumference or area and derive the complete circle plus arc, chord, sector and segment measures.
The calculation runs locally. Exact-integer tools avoid floating point; decimal and transcendental tools report rounding limits.
Method and verification guide
How the Circle Calculator works
D = 2r, C = 2πr and A = πr². Arc and sector measures multiply the full-circle quantity by θ/360. The calculator keeps the intermediate values visible so you can reproduce the answer independently.
Interpret the result
All main circle measures are determined by any one positive radius-equivalent input.
Check the assumptions
Segment results describe the minor segment for angles up to 180° and the corresponding directed formula above that range.
Local calculation
Everything runs in this browser. Inputs are not sent to an external calculator.
Rounding
Displayed values may be rounded for readability while calculations use full floating-point precision unless the tool explicitly uses exact integers.
Scope
Segment results describe the minor segment for angles up to 180° and the corresponding directed formula above that range.
Simple by design
Three steps to a clearer number.
Enter your details
Use realistic values in each field. You can change them anytime.
Calculate instantly
The formula runs locally, so there is no account or waiting time.
Use the result
Treat the answer as a practical estimate for your next decision.