How is range measured in League of Legends? [duplicate]

league-of-legends

I know different games use different techniques and units of measurement. In Starcraft II one range for attack is about the width of one zergling. In Guild Wars the range is some fraction of the compass or aggro range (Spears have ~0.7x aggro range, longbows ~1.2x)

Most (or all?) meelee champions in LoL have an attack range of 125. The attack radius for range champions differs quite a bit, e.g. 425 for Urgot, 510 for Twisted Fate and 550 for Heimerdinger.

I wonder how is range exactly measured in League of Legends?

I can't tell you exactly how much a unit is on the screen, there are however quite a few ways to get an idea of what different range represent.

A "distance unit" is a predefined distance on the field of justice. Range and speed are calculated from this unit.

Movement speed

Movement speed is the amount of "distance units" you travel in one second

Spell range

There are many spells with many different ranges. To get an idea of the range it represents, put you mouse over the spell and a circle will show you the range it represents. Here is an example for Kassadin's null sphere with a range of 700 : Kassadin's null sphere range

Auto-attack range

There isn't anything that can show you directly the range you have. You have to get use to it and compare it with your spells range to get a good idea.

To get an idea of what 125 represents, Nunu's consume has a range of 125 : enter image description here