Ellipse Perimeter Calculator
Result
Calculate approximate perimeter from Semi-major axis a, Semi-minor axis b.
Formula
- Enter Semi-major axis a, Semi-minor axis b using consistent units. This tool calculates approximate perimeter as pi × [3(a+b) − sqrt((3a+b)(a+3b))] (Ramanujan approximation). All geometric dimensions should be positive and in the specified units.
- The main inputs are Semi-major axis a, Semi-minor axis b. Enter them in the units and format shown in the calculator.
- Keep comparable quantities in compatible units whenever the formula combines or compares them.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Ellipse Perimeter
- Semi-major axis a: 5
- Semi-minor axis b: 3
Using Semi-major axis a = 5, Semi-minor axis b = 3, the calculated result is Approximate perimeter: 25.5269863938.
Sample result: Calculating…
Frequently asked questions
What does the Ellipse Perimeter calculate?
Calculate approximate perimeter from Semi-major axis a, Semi-minor axis b.
Which values should I enter?
Enter Semi-major axis a, Semi-minor axis b using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: pi × [3(a+b) − sqrt((3a+b)(a+3b))] (Ramanujan approximation).
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.