# Chess Ratings - How They Work

• erik
• | Aug 23, 2007
• | 197812 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):

• 3 years ago

science_man_88   Yes obviously I read it,but my ratings were going slightly strange so the article didnt cover everything to what was going on with my ratings.

• 3 years ago

PCL91  did you read the article ? it's clearly stated in it why this might happen

• 3 years ago

I have played about ten online games so far and for example in the rating adjustment if I lose, my rating goes down by sometimes 80 points, that is when I am playing someone who is a lower rating then mine, however my friend has an account on chess.com and when he is playing someone who has a much lower rating then him, in his rating adjustment if he loses his rating would only go down by about 18 points.  Why is this ??? Any answers much appreciated.  Thanks.

• 3 years ago

Well, I've had some interesting and helpful replies ...Thank you very much all who have contributed. I hope Chess Com does not scoop it all up before I, and others interested,  have had a chance to make some notes. Leochap (He with the lowly rating)

• 3 years ago

@snoopchuck: Your account will only be rated if you play rated games.

• 3 years ago

Hi, does anyone know how to change an account from an unrated one to a rated one? Thanks a lot!

• 4 years ago

:( Honestly!!! why they are aborting my game in Blitz :(  they're not even have a high points.

• 4 years ago

I do not think it is possible to play 1000 games a day. There are only 1440 minutes per day, and even if each of the games lasts only one minute each, they still have to sleep and eat.

• 4 years ago

the live ratings  r the only ratings that mater  30 mins each side  not two days to move . on line chess is the real  deal

• 4 years ago

hi. could any explain why my rating in live chess has never changed and i have been playing along time now. forthy games at least

• 4 years ago

I like how you said Kasparov has "about" a 100% chance of beating your 4 year-old daughter.

• 4 years ago

How does chess.com ratings compare to FIDE ratings?

It seems that chess.com ratings are shifted down. Is this because players start with 1200 or is it more due to the different math method of rating calculation?

Regards,

Emilson

• 4 years ago

I am glad that I rediscovered you! It's been a long time and I have been playing a (little) chess on  Pogo.com. They don't have problems initiating a game when my opponent plays the white pieces. You do, in all due respect. I am waiting for my opponent to make his move with the white pieces. Why haven't you set up things in a working manner here that will notify him that I have started a game using the black pieces, and have to wait for him to make his, i.e. the first move? What is the matter here? Today is February 25, 2012. I await you quite necessary reply, after you repair the problem, please.

• 4 years ago

ssdeep u played with an opponentof lower rating! that's reason for droping down of ur current rating.

• 4 years ago

Thank you for the explanation.

• 4 years ago

hi dear popskirk ! please take into account the number of opponent pieces u have knocked down and their value in total !! this may go to help u to find out the accuracy of the points number  U earned!!

• 4 years ago

Veeeery interesting! I will not read the long version of how your rating system works,but it seems to work OK as far as I'm concerned.

• 4 years ago

Help! Just joined  awhile ago ...I played in Blitz game and wins 4 so far :p   Please, can anyone tell me why it says on the top left corner says "Standard". Isn't it should be "Blitz" ?  And why my Online rating is Unrated....(well, i never win yet :p ) ..but is there any setting that i should  do?..I didn't really filled up the  settings when i started the game .What does it mean by Max.of games, Opponent rating (min-max) , Time per move?. Do i really have to filled it up? or not really..

Thank you, I'll appreciate it if you can help me.xxx

nen407

• 4 years ago

hi Fozor! Thanks for your query!! Your needed solution is already posted by Blackenne , US.Please look on the previous posting preceding yours query!!

• 4 years ago

hi French Fozor, please click on the name tab of your opponent on the chess board top corner and then his ratings will come up to your notice!!