Geometry method
The center is the intersection of two perpendicular bisectors. A determinant form is used to solve the coordinates and radius.
Circle Through Three Points Calculator
Recover the center, radius, diameter, and circumference of a circle from three measured points, with scale-aware detection of collinear or nearly collinear inputs.
Part of Workshop Calc ↗Ready to calculate
Enter the dimensions, then calculate to see a checkable result.
Estimate only:Use appropriate measurement uncertainty and independently verify critical fitted geometry.
02 / Method & limits
Make the calculation checkable.
Example
Points (1, 0), (0, 1), and (−1, 0) define a circle centered at (0, 0) with radius 1.
Limits & checks
- Collinearity tolerance must scale with the magnitude and spread of the input coordinates.
- Nearly collinear measurements can amplify small measurement errors into a very large radius.
Sources & review
Last reviewed: 2026-07-19