Ellipse Area Calculator
The area and approximate perimeter of an ellipse from its two semi-axes.
Result
Area
47.12
Perimeter (approx.)
25.53
How it works
Area = π · a · b
An ellipse is a stretched circle. Its area is π times the two semi-axes; the perimeter has no simple exact form, so we use Ramanujan’s accurate approximation.
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Frequently asked questions
What are a and b?
The semi-axes — half of the longest and shortest diameters of the ellipse.
Is the perimeter exact?
No exact elementary formula exists; this uses Ramanujan’s approximation, accurate to a tiny fraction of a percent.
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