Ellipse Area Calculator

Where a is the semi-major axis and b is the semi-minor axis.

Calculate the area of an ellipse with semi-major axis 8 cm and semi-minor axis 5 cm:

Result: 125.66 cm²

1. Enter the semi-major axis (half the longest diameter)
2. Enter the semi-minor axis (half the shortest diameter)
3. Click "Calculate" to see the ellipse area

• Circumference approximation: $\\\\pi \\\\times (3(a+b) - \\\\sqrt{(3a+b)(a+3b)})$
• Eccentricity: $e = \\\\sqrt{1 - \\\\frac{b^2}{a^2}}$

• Planetary orbit calculations
• Lens and mirror design
• Architecture and design
• Statistical ellipses in data visualization

What if a = b? The ellipse becomes a circle with area $\\\\pi r^2$.

Can I enter the full axes instead? Yes, divide each by 2 to get the semi-axes.

How accurate is the circumference? The formula given is an approximation; the exact value requires elliptic integrals.

What units should I use? Any consistent unit. Area will be in square units.