# Chess Ratings - How They Work

• erik
• | Aug 23, 2007
• | 198698 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):

• 5 years ago

Hi, G Raymond ! If the opponent resigns you get point !!

Hi, mufid30 ! When you win a game any way,you get point!!

• 5 years ago

Thank you for your explanation. Now...how do chess ratings work?

• 5 years ago
[COMMENT DELETED]
• 5 years ago

It is not if the number of moves is bigger than 3 or 4. But if there are only 3 moves and you win on time or thanks to abortion you won't gain any rating points.

• 5 years ago

That is important if i won with a checkmate, abort or time?

• 5 years ago

• 5 years ago

Thx for the response Mike

• 5 years ago

No it won't.

• 5 years ago

Thx for the useful article. I used to play club chess a fair while afo and just joined chess.com. I would like to understand whether the rating calculated and allocated by the site is official. I.e. will it be accepted for playing normal club chess?

• 5 years ago

thx i got some info

• 5 years ago

how can i veiw my current ratings?

• 5 years ago

Thanks for explaining it!

• 5 years ago

No, I think it has to be at least 3 moves!

• 5 years ago

Do you get rated when your opponent time run out after two move?

• 5 years ago

P.S. CHESS PLAYERS CHEAT ON THEIR RATINGS,IN FACT IT'S  QUITE COMMON.CHECK PROFILE OF YOUR OPPONENTS.IN OVER THE BOARD-LIVE CHESS-YOU HAVE TO WATCH SOME OF THE MORE NIMBLE FINGERED( OH YEA! THEY MOVE PIECES!! ) AS FOR KASPAROV AND MY DAUGHTER. WHO EVER STARTED THAT GOSSIP NEEDS A GOOD WHIPPING. ALSO WATCH OUT FOR THOSE WHO WILL ONLY PLAY WHITE PIECES--ABORT,ABORT!

• 5 years ago

I don't really care how the ratings or calculated, a more interesting question is when are they calculated.  In standard games an opponent's rating may go up as his other correspondece games finish.  My question is do I get credit for beating the 1200 level player as he was rated in the beginning of the match or for the 1800 level player as his rating was just prior to the end of our match?  I feel this is a good question or I would not bring it up.

• 5 years ago

Bogie, I am not sure about theoretical but you can find practical highest and lowest ratings in my blog post here: http://blog.chess.com/driv4r/highest-and-lowest-rating-on-chesscom

• 5 years ago

So what are the lowest and highest theoretical and practical ratings?

• 5 years ago

platolag, I have also talked about it a lil in my post below but definitely yes for 4, 5 and 7 moves and defo no for 1 move. I might be wrong here but probably no for 3 moves.

• 5 years ago

by GRaymond - 8 months ago
Treviso Italy

Member Since: Mar 2010
Member Points: 352

Question: "is it possible to win points when the opponent resigned after 1 (one), 3 (three), 4 (four) and 5 (five) or 7 (moves) ?