Maths & numbers
Ellipse calculator
Calculate area and an approximate ellipse perimeter.
A clear answer. Here’s how.
Inputs are semi-axes, half the full widths. Area = πab. Perimeter uses Ramanujan’s second approximation: π(a+b)[1+3h/(10+√(4−3h))], h=((a−b)/(a+b))². The perimeter is approximate.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- First semi-axis
- 5
- Second semi-axis
- 3
Example result
- Area
- 47.1238898038
- Approximate perimeter
- 25.5269988628