If you have an iPhone, IBeacons work quite well, but that’s a topic for another thread. 
Most “receiving station” apps can recognize 3 distances, which are really measures of signal strength, but work out to approximately:
Immediate: about 3 cm
Near: about 3 m
Far: Max range, typically about 12 m
And can also use Region detection where multiple IBeacons are used to define a larger area.
For one use case, I use Near to detect when I get to the end of the wheelchair ramp at my front door.
But it all depends on which app you use with them.
Here is a recent discussion: