Matchmaking Math: How Elo, Glicko and CS2 Rank Systems Work

When you click ‘Play’ in an online game, an algorithm will pick your team and your opponents. For many players, the most visible result of that math is their CS GO rank, the badge that sums up hundreds of hours of play in a single label. Behind it sits a family of rating systems that started in chess and now power matchmaking in almost every competitive game. Understanding how these rating systems work is the key to understanding why your rank changes the way it does.

Why Online Games Need Skill Ratings

The fundamental aim of matchmaking is to get games set up where both teams have a realistic chance of winning. If the players are too disparate in ability, then the games can end up being one-sided and very frustrating. A rating system takes each player’s results and turns them into a number, which can then be used to group players of a similar ability together.

Elo: The Chess Classic

Physicist Arpad Elo invented the Elo system, which the chess federations began to use in the 1960s and 70s. Each player has a rating which is adjusted up or down after each game. You get more points for beating a higher-rated player than you do for beating a lower-rated one, and you lose more points if you lose to a lower-rated player. It’s a very simple system but it has one rather fundamental flaw in that it treats a newcomer and a veteran with the same rating as being equally good.

Glicko and Glicko-2: Adding Uncertainty

In the 90s, Mark Glickman came up with the Glicko system to deal with that problem. It’s not just a rating; it’s a rating and a rating deviation. The rating deviation tells you how certain the system is about a player’s skill. New players or players who have been inactive will have a high degree of uncertainty, and so their ratings will change quite rapidly. The ratings of more experienced players will move more slowly. Glicko-2 added in a volatility value to indicate how consistent a player’s results are. A lot of people think that CS:GO matchmaking is based on a Glicko-2 type of system, though Valve has never disclosed the actual formula.

How Counter-Strike 2 Does It: Competitive vs Premier

CS2 uses two ranked modes. In Competitive, players earn one of 18 classic CS2 ranks, also known as skill groups, from Silver I to The Global Elite, and the rank is tracked separately for each map. Each map has its own rank. Premier uses a single CS Rating rather than badges. That rating is updated after every match and is displayed in color bands (silver/light blue through to blue, purple, pink, red and gold above 30k). The way the number is formatted makes it very easy to see how each win and loss affects your rating.

Why Your Rank Sometimes Feels “Wrong” and How to Climb

Hidden factors such as uncertainty mean that two players of the same rank could end up gaining or losing very different amounts following the same match. You rank up much quicker by beating the higher-ranked opposition, and you get hurt much more by losing to the lower-ranked. The best way to go up is to play regularly, play a few maps, talk to your team, and learn from your mistakes. Eventually, the system will match your actual skill, and your rank will feel far less random once you’ve got a feel for it.