Guild Wars 2

Is there an easy way to tell this or is it just eyeballing it after you get use to using it so much??

Eyeball the minimap. The range is about the end of your cone of vision in the minimap.

Zoom in all the way on your minimap. The range is approximately the distance from the top to the bottom.

Running with no speed buffs it is a 13 second count if running in a straight line.

Maximize the box your minimap is in. Zoom all the way in. Put a waypoint at the edge of the minimap. Drop your portal where you are standing, run to the waypoint, drop the other end. If going at angles, err on the side of caution, go short.

Practice in lion’s arch, using various landmarks as your start/end targets until you are comfortable. Divinity’s Reach is another good practice area, lots of good flat space. Make sure you’re spec’d to reduce the recharge on it, at least during practice time. It helps tremendously.