Ratings

The basics:

You can have many different ratings on the ICC. There are ratings for bullet, blitz, standard, 1-minute, and 5-minute, which are different speeds of regular chess. There are ratings for bughouse, loser's, and wild, which are for chess variants. See help definitions for an explanation of what these mean. Type finger to see your current ratings.

The [need] column indicates how many rated games are needed in a particular cateogry for the rating to become active for this month or week. Only active ratings are listed in the best list or a best list for a pariticular category, like best bullet.

To get a rating in one of these categories, you only need to play a rated game. Left click on the underline to learn how to seek a game

Ratings usually range from 600 to 3500 on ICC, but there is theoretically no limit at either end. You can type "best" to see the highest-rated players on ICC. You can type rank to see where you stand among ICC members. The ICC command statistics shows the average ratings. Type it into the main console.

Ratings on ICC are similar to the USCF and FIDE, but are totally separate. Read help survey for a statistical comparison.

A player's rating is "provisional" if he/she has played less than 20 games in a given category. A player's rating is "established" if it is based on 20 or more games. A different formula is used to calculate ratings for established and provisional players, which can result in very unusual results when either player is provisional. See help provisional for some information about provisional ratings.

If you want to know how your rating will change after playing a particular person, see the page on assessing potential rating changes



Everything you ever wanted to know about rating formulas, but were afraid to ask:

The rating during the provisional period is the average of a set of values, one for each game played. The value for a game against an established player is the opponent's rating plus 400 for a win and minus 400 for a loss. For a game against another provisional player, the value is moved towards the previous average to lessen the impact of the unreliable result. Extra points are then added to the rating for the purpose of keeping the average rating of all established active players close to 1600. In particular, 1/5th of 1600 minus the current average is added to the rating.

To explain the established period requires the use of a formula. Suppose your rating is r1, and the opponent's is r2. Let w be 1 if you win, .5 if you draw, and 0 if you lose. After a game, your new rating will be:

1 r1 + K * [ w - ---------------------- ]
1 + 10 ^ ((r2-r1)/400)

I still need to explain the variable K. This is the largest change your rating can experience as a result of the game. The value K=32 is always used for established player versus established player. If you're playing a provisional player, the factor K is scaled by n/21, where n is one plus the number of games your opponent has played. See also "help k-factor".

This formula has the property that if both players are established then the sum of the rating changes is zero. It turns out that if the rating difference is more than 719 points, then if the strong player wins, there is no change in either rating.

Note that during the provisional period, BEATING a player whose rating is more than 400 points below yours will DECREASE your rating. This is a consequence of the averaging process. It's useful too, because it prevents the technique of getting an inflated provisional rating after one game, and then beating 19 weak players to get an established rating that is too high.

Your initial rating that you gave at registration time is counted the same as one draw against a player of that rating, brought to within the range 1000-2200.

Other info on ratings:

"help FIDErating" for the top 100 FIDE players from the latest rating list.
"finger ROBOadmin" for info on the searchable FIDE rating list on ICC.
"help survey" for a comparison of ICC, FIDE, and USCF ratings.

See Also:
How to play chess on ICC
ratings - command line help