Use this convertor to convert the units of surface from American/English units to the metrical unit system (SI).
In the calculator mentioned below, you can calculate the area of a circle. You need to fill in the radius. You can also calculate the radius if you fill in the area. It does not matter in what units you fill in. You only have to know that the unit of the surface is derived of the length. If you fill in m, than the surface is m2.