# Circumference of Ellipse

The **circumference of an ellipse** is calculated by formulas but the formulas are only approximate. In practice you can read different formulas in different books. To calculate the **circumference of an ellipse** we need to know a length of its semi-major and semi-minor axis. For example, to know the length of an elliptic running track or any playground, you can use this formula. The elementary unit is one metre (1 m).

## Circumference of Ellipse - formula

**Circumference of Ellipse** ≈ π × √2 × ((semi-major length of a)^{2} + (semi-minor length of b)^{2})

C ≈ π × √2 × (a^{2} + b^{2})