Ellipse Calculator
Compute ellipse properties quickly from an equation, parameters (a, b, h, k), or coordinate points. Includes interactive graph, step-by-step derivation, and exportable results.
Enter equation in standard form: (x-h)²/a² + (y-k)²/b² = 1
Quick Links
Results
Graph
Frequently Asked Questions
How do I find the foci of an ellipse?
Use c = √(a² - b²). For a horizontal ellipse the foci are at (h ± c, k).
What is the formula for the area of an ellipse?
A = π a b.
How accurate is the circumference value?
The calculator shows Ramanujan's approximation and one other method — both are highly accurate approximations.
What is the difference between a and b in ellipse parameters?
a is the semi-major axis (half the longest diameter), b is the semi-minor axis (half the shortest diameter).