## Enter your coordinates

## Distance between the two points

## Choose two points on the map

## Accuracy calculations

If you calculate the distance between (90, 0) and (-90, 0) you get 20015 km. If you divide this with PI (~3.41) then you get 6371 km.

According to wikipedia the globally-average earth radius value is usually considered to be 6371 km. So we have gotten the right result.