Kill to Death Ratio

Kill to Death ratio (often referred to as K/D-Ratio) is simply the number of kills one has divided by the number of deaths. As of now, League of Legends does not track this information, so it must be calculated manually.

Usage
For DPS based characters, such as Assassins or Carries, it is one of the most effective ways to evaluate a player's quality. Players with these types of characters should be reaching a K/D-Ratio higher than 1. Generally you can say: The higher it is, the better the player.

Other types of champions, such as Pushers, Tanks, and Support characters do not emphasize a high KDR as part of a successful game, but take other factors in mind.Supports and Tanks should have more than double their deaths in assists to be considered 'doing their job'. Pushers, on the other hand, should be evaluated by the amount of towers they pushed, not their KDR.

In a game, comparing the KDR of both teams as a whole is useful as a rough guide of how well both teams are doing but does not determine a winning team; often the team with more pushing power will come out victorious.

Examples
Keep in mind that assists play an important role that can not be seen by just calculating the K/D-Ratio. For example, Player 3 arguably did a better job than Player 1, though he has a lower K/D-Ratio.
 * If Player 1 scores a 6:2:5, the K/D-Ratio is 6 / 2 = 3.0.
 * If Player 2 scores a 2:6:8, the K/D-Ratio is 2 / 6 = 0.33.
 * If Player 3 scores a 4:2:17, the K/D-Ratio is 4 / 2 = 2.0.