Which axes to enter
Enter the semi-major and semi-minor axes, meaning half of the full width and half of the full height through the center.
Example
If the semi-major axis is 5 and the semi-minor axis is 3, the area is pi x 5 x 3, or about 47.12 square units.
Common mistakes
If you measured the full width and full height of the ellipse, divide each by 2 before entering the values. The calculator asks for semi-axes, not full axes.
Limitations
The formula assumes a true ellipse. Irregular ovals, hand-drawn shapes or landscaped curves may need measurement or approximation by smaller shapes.
Last reviewed: 2026-05-17