Ellipse Area Calculator
Measure the surface area enclosed by an ellipse using the lengths of its semi-major and semi-minor axes.
Use for geometric estimates; real shapes may vary.
Examples
- a = 5.2 cm, b = 3.8 cm ⇒ 62.07 cm²
- a = 12 ft, b = 7 ft ⇒ 263.89 ft²
- a = 2.5 m, b = 2.5 m ⇒ 19.63 m² (circle case)
FAQ
What are semi-axes?
They are half the full width and height of the ellipse. Measure the longest radius for a and the shortest for b.
Can I enter negative numbers?
No. Axis lengths must be zero or greater because they represent distances.
Does the calculator support different units?
Yes. Enter any unit you like—the output returns the same unit squared.
How precise is the result?
Precision depends on your input measurements; the formula itself is exact for ideal ellipses.
Additional Information
- The area of an ellipse equals π multiplied by the product of the two semi-axis lengths.
- Use the same unit for both axes—centimeters, meters, inches—to keep the result consistent.
- For a perfect circle, the semi-major and semi-minor axes match the radius, so this formula returns πr².
- Elliptical areas commonly describe planetary orbits, racetrack designs, and architectural arches.