Perimeter of an Ellipse Calculator
Enter the semi-major and semi-minor axes of an ellipse to calculate its perimeter using Ramanujan's highly accurate approximation.
Ellipse Dimensions
m
m
Result
Enter the semi-major and semi-minor axes to see the perimeter.
Perimeter (Circumference)
Diagram
| Property | Value |
|---|---|
| Semi-major axis (a) | |
| Semi-minor axis (b) | |
| Eccentricity (e) | |
| Area | |
| Perimeter |
Summary
Enter the semi-major and semi-minor axes of an ellipse to calculate its perimeter using Ramanujan's highly accurate approximation.
How it works
- Enter the semi-major axis (a) — the longest radius of the ellipse.
- Enter the semi-minor axis (b) — the shortest radius of the ellipse.
- Choose your preferred unit of measurement.
- The tool applies Ramanujan's formula: P ≈ π × [3(a+b) − √((3a+b)(a+3b))].
- The perimeter, eccentricity, and area are displayed instantly.
- Copy the result with one click.
Use cases
- Calculate the length of an oval running track or garden path.
- Determine how much trim or edging is needed for an elliptical table.
- Estimate ribbon or framing material for oval picture frames.
- Solve geometry and calculus homework problems involving ellipses.
- Compute orbital path length approximations in basic astronomy.
- Find the border length of an elliptical pool or fountain.
- Verify CAD measurements for elliptical architectural features.
- Cross-check ellipse perimeter estimates in engineering drafts.
Frequently Asked Questions
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Last updated: 2026-05-23 ·
Reviewed by Nham Vu