# Area of Polygon by Drawing

Can you draw your polygon? Maybe you know the coordinates, or lengths and angles,

either way this can give you a good **estimate** of the Area.

Use the "Edit" button below to manually edit the coordinates, or to enter new coordinates of your own.

images/area-coords.js?mode=area

*Note: due to computer rounding errors the last digit is not always correct.*

## What is Regular, Concave, Complex?

When all angles are equal and all sides are equal it is **regular**, otherwise it is** irregular**

When any internal angle is greater than 180° (it points inwards) it is **concave**. (*Think: concave has a "cave" in it*), otherwise it is **convex**.

When the boundary crosses over (so the polygon intersects itself) it is **complex**, otherwise it is **simple** like most polygons we deal with. Many rules about polygons don't work when they are complex.