what is min. & max. chess rating of a player & how is it calculated ?

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rocky0chess

Jan 20, 2014

hi friends,

please share the information :

1) what is minimum & maximum chess rating of a player & how is it calculated ?

wasted_youth

Jan 20, 2014

Here you go!:

(Wikipedia)

Elo gives an example of calculating the rating of Lajos Portisch, a 2635-rated player, in an actual tournament of 16 players, and scored 10½ points. First the difference in rating is calculated for each other player, subtracting the other player's rating from Portisch's rating. Then the expected score against each player is determined from a table, based on this rating difference. For instance, one opponent was Vlastimil Hort, who was rated at 2600. The rating difference of 35 gave Portish an expected score of 0.55. The expected score is summed for each opponent, giving Portisch a total expected score of 9.66. Then the formula is:

new rating = old rating + K×(W-W_e), where K=10, W=actual score, and W_e=expected score.

Portisch's new rating (Elo 1978:37) is 2635+10×(10.5–9.66)=2643.4.

Linear approximation

Elo devised a linear approximation to his full system. With that method, a player's new rating is

$R_{ new } = R_{ old } + \frac{ K }{ 2 }( W - L + \frac{ 1 }{ 2 } \frac{ \sum_i D_i }{ C } )$

where R_new and R_old are the player's new and old rating respectively, D_i is the opponent's rating minus the player's rating, W is the number of wins, L is the number of losses, C = 200 and K = 32. (Elo 1978:28–29)

The example of Portisch with K = 10, with the sum of the rating differences being 1620 is:^[3] (Elo 1978:39)

$2635 + \frac{ 10} { 2 } [ 10.5 - 4.5 - \frac{ 1 }{ 2 } \frac{ 1620 }{ 200 } ] = 2644.75$

The USCF used a modification of this system to calculate ratings after individual games of correspondence chess, with a K = 32 and C = 200.