GPS coordinates: 1km square around a point

Question

I was hoping someone out there could provide me with an equation to calculate a 1km square (X from a.aaa to b.bbb, Y from c.ccc to c.ccc) around a given point, say lat = 5

Answer 1

TL;DR

10 km = 0.08999 radius from a certain geopoint. This calculation is only based on latitude values and applies only to geopoints with WGS84 projection.

More details

If you want a more accurate answer you must have to calculate it by building a function of some sort. However it still don't guarantee because people even quarrel for the degrees of error. Taking altitude into account, mercator or not, etc.

Caution

The value above is just a rule of a thumb so don not use it for critical applications.

Reference

GIS StackExchange, How do I calculate the bounding box for given a distance and latitude/longitude, answer by David the Australian developer