# Chess Ratings - How They Work

• erik
• | Aug 23, 2007
• | 198081 views

Like it or not, we ALL have a chess rating. You may not care at all about your rating, or you may be whining every time it goes down in the slightest. You might be someone who plays a game a year, or someone who plays 1,000 a day. Still, there is a number out there that represents how well you play chess. Well, that's the theory, anyway.

To understand chess ratings you have to understand two things: #1 - that you have a TRUE rating that perfectly represents your strength of play, and #2 - that that TRUE rating will never be known and so we have to use statistics to get as close as possible to the truth. I'm writing this article in response to many people who ask about ratings and need a simple explanation of how they work. (I only know about all this because of a recent super-in-depth statistics course I took and my research in building Chess.com!)

There are two main rating systems, and each one has its merits.

The Elo System (used by the United States Chess Federation, FIDE, and many other online chess sites) is popular for two reason - it has been around for a long time, and it is simple. The idea is this: given two chess players of different strengths, we should be able to calculate the % chance that the better player will win the game. For example, Garry Kasparov has ~100% chance of beating my 4-year-old daughter. But he may only have a ~60% chance of beating another Grandmaster. So when playing that other Grandmaster, if he wins 6 games out of 10, his rating would stay the same. If he won 7 or more, it would go up, and 5 of less, his rating would go down. Basically, the wider the spread of the ratings, the higher percentage of games the higher rated player is expected to win. So to calculate a person's rating after playing a few games you calculate the average ratings of his opponents, and then how many games he was expected to win, and then plug it into a formula that spits out the new rating. Simple enough. Well, it turns out, that is maybe TOO simple.

I wish there was some simple analogy to explain all this, but there isn't. It all comes back to this: you have a theoretically exact chess rating at any given moment, but we don't know what that is and so we have to use math to estimate what it is. There are really smart people out there who work on this stuff for a living, and at the end of it all we get to put their proven methods into our code so that we can all enjoy knowing what little numbers next to our name we deserve.

If you want to read more, check out these articles (WARNING - SEVERE NERD CONTENT AHEAD):

• 10 months ago

I am one of those people who cares less about his rating and simply enjoys playing the game. So for those of you who are discouraged by chess.com's rating system then maybe you should try caring more about the game and less about some silly math formula that uses numbers to determine your "skill". Just food for thought. I find not giving a hoot about those little numbers next to my name allows me to actually enjoy the game at hand rather than racking my brain trying to combat some math formula that I probably couldn't figure out with the help of a super computer.

In short, just the play the game. I bet you'll have more fun then. ;)

• 11 months ago

I agree with Bartcore. Usually, I can't improve unless I've been playing for months nonstop, gaining experience. But when I first start out after a long break, my rating will plummet. It then takes me a good YEAR just to get my rating back up to where it is, and every time I lose a single game I practically have to start over. I've lost almost all motivation to play chess as a result (Note that I haven't had a teacher in about 10 years, and I only ever learned the basics). I haven't played here for about six months, and I only just came back because I was in a tournament taking forever. If you look at any of my games, you can tell I'm screwed already. It's this sort of thing that makes people give up chess.

I kinda wish there was a setting where you could make it so you never see your own rating, or the ratings of others. Just so you could play without that pressure.

• 11 months ago

I find the glicko system to be bad. I have played chess for some time now, staying at a low level. However, last few months I have made drastic improvements. Because of the glicko system, it is going to take years to elevate my rating to a decent level, even though I am already beating 1750 rated players over the board.

I also find that my low rating demotivates me a little.

• 11 months ago

I'm new to chess.com and don't have a rating. I just played my first game against an opponent with a 1400 or so rating. Will i get a rating now?

• 11 months ago

Hi

We wish You pay attention that regressing rating of player

is not that obviouse idea. Think that rating of player accord

his level in chess. His rating must not depend on games's

result because his level is real (i.e. really exists). Allowing

rating to go down we say actually that level of player is virtual.

• 12 months ago

thanx for replying to our chess cares ! important  article

• 12 months ago

For those of you that think it is not bad, ask yourselves why the inventor has publically stated that it is flawed and he went on to invent two or more new systems to replace it. Just look it up. It is all documented online.

• 13 months ago

I think glicko system is not bad its more efficient

• 13 months ago

I think glicko system is not bad its more efficient

• 13 months ago

I think glicko system is not bad its more efficient

• 13 months ago

I think glicko system is not bad its more efficient

• 13 months ago

I think glicko system is not bad its more efficient

• 13 months ago

Charles,

I don't think that effect really matters after the first handful of games are played. I always have the same number of points on the line for each game I play, so I would in fact start and end with the same rating in your example. This is because the points on the line for each game seem to be rounded to an integer value, so small RD changes are truncated.

• 13 months ago

The biggest problem with the first Glickman system which is used here is that is automatically deflationary. Deflationary systems are bad.

Here is the proof.

In a normal system: Lets say you play a person 200 points below you. You are expected to win 3 of 4. You lose the first game and win the next 3. With a normal system, you will end up with the same rating that you started with.

With the first Glickman system (used here), the RD value drops with each game and you end up with a rating below your starting rating. Thus, the rating system used here is deflationary which means all ratings of participants that are holding steady in their playing strength will drop over time.

I don't know why Chess.com and Freechess.org continue to use this system when it is clearly bad and has been abandoned by its author. Mr. Glickman has created newer versions of his sytem that solve that problem and admits that in his first system he forgot to include the concept of "practice makes perfect". He only included "practice makes you consistent" which means the more you play the more your rating should stay the same.

This is not how people actually perform. There is lots of data on the net showing that people start getting consistent then gain a noticable strentgh boost and become inconsistent again. Then, the process repeats. Thus, real life is practically the opposite of the first Glickman system.

• 13 months ago

Jimmy,

How you lose doesn't matter to the rating system. It only cares if you win, lose or draw.

• 13 months ago

i cant be bothered going into details, i play chess and watch youtube at the same time, i am complete amateur...but, please, tell me just one thing about ratings: is it better to resign when i am sure to lose, or play to the bitter end? will my rating go down faster if i am check mated more often, or will it go down faster if i resign more often?

• 16 months ago

my rd is 34

• 16 months ago

hmm

• 16 months ago

Really a nice article!

• 17 months ago

Proxima-Centaurus,

Ratings for players are calculated independently (there is no law of conservation of rating points). If you are a newb, your rating is very uncertain, and therefore swings up or down quite drastically until it settles on an accurate figure. Your opponents rating may be more certain, and therefore it only goes up or down a few points at a time. I tend to have about 8 points on the line for each game because I have played a few hundred games and my playing strength is pretty consistent within about a fifty point rating range.