Ellipse Area Calculator
Calculate the area of an ellipse
Area
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Ellipse Area Calculator Formula
Area of an ellipse:
A = π × a × b
How to Use This Calculator
- Enter the semi-major axis (a) — the longer half-axis from the center to the edge.
- Enter the semi-minor axis (b) — the shorter half-axis from the center to the edge.
- Click Calculate Area to see the result.
Frequently Asked Questions
What are the semi-major and semi-minor axes?
An ellipse has two axes of symmetry. The semi-major axis (a) is the longer distance from the center to the edge, and the semi-minor axis (b) is the shorter distance. Together they define the shape: a circle occurs when a = b.
What if a = b?
When both axes are equal, the ellipse is a circle. The formula A = π × a × b becomes A = π × r², which is the standard circle area formula. You can also use our dedicated circle calculator for that case.
Does it matter which axis is a and which is b?
No — the formula π × a × b is symmetric, so the result is the same regardless of which axis you label a or b.
What units are used?
This calculator is unit-agnostic. The result is in the square of whatever unit you use for the axes.
What is the circumference of an ellipse?
Unlike a circle, the circumference of an ellipse has no simple closed-form formula. A common approximation is C ≈ π(3(a+b) - sqrt((3a+b)(a+3b))), known as Ramanujan's approximation. This calculator computes area only.
Can I share my calculation?
Yes. After clicking Calculate, the URL updates with your input values. Copy and share the URL to let anyone else see the same pre-filled form and result.