Ellipse Calculator
Area, perimeter and foci of an ellipse.
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Results
- Area
- 87.9646
- Perimeter (approx.)
- 35.2032
- Eccentricity
- 0.82065
- Focus distance from centre
- 5.7446
- Foci at
- (±5.745, 0)
Quick answer
An ellipse has area πab; its perimeter has no simple closed form, so Ramanujan's approximation is used.
Area = πab
How to use the Ellipse Calculator
- 1Enter the semi-major axis (half the long diameter).
- 2Enter the semi-minor axis.
- 3Read area, perimeter and foci.
Frequently asked questions
Why is the perimeter approximate?
The exact value needs an elliptic integral; Ramanujan's formula is accurate to a few parts per billion.
What is eccentricity?
How stretched the ellipse is: 0 is a circle, close to 1 is very elongated.