- 03 Jan '08 01:46 / 20 edits
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Calculating your Rating

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New Rating = Old Rating + K * (Score – Win Expectancy)

K is a constant (32 for 0-2099, 24 for 2100-2399, 16 for 2400 and above)

Score is 1 for a win, 0.5 for a draw and 0 for a loss.

The Win Expectancy is calculated using the following formula:

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/400)+1)

For more, see FAQ

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Explanation of Symbols

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Rating Difference – The difference in rating between you and your opponent at the conclusion of the game

HR(W)– Higher rated player wins said points

HR (L) – Higher rated player losses said points

LR (W) – Lower rated player wins said points

LR (L) – Lower rated player losses said points

Game Drawn – Game is drawn. Higher rated player losses said points / Lower rated player gains said points

**Example(1):**

Your rating: 1400

Opponents rating: 1415

Status: You win!

Your rating falls between 0 and 2099. The difference between you and your opponent’s rating is 1415-1400 = 15, you are the player with the lower rating. 15 falls between 11-32 therefore you gain the points in the “Lower Player” Column for the number, 17.

**Example (2):**

Your Rating: 2200

Opponent's Rating: 1800

Status: Game Drawn

Your rating falls between 2100 and 2399. The difference between you and your opponent’s rating is 2200-1800 = 400, you are the player with the higher rating. 400 falls between 365-428 therefore you lose the points in the "Game Drawn" Column, 10.

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Rating Calculations [0-2099]

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Rating_______HR(W)____Game___HR(L)

Difference____LR(L)____Drawn____LR(W)

0 - 10 ________ 16 ______ 0 ______ 16

11 - 32 _______ 15 ______ 1 ______ 17

33 - 54 _______ 14 ______ 2 ______ 18

55 - 77 _______ 13 ______ 3 ______ 19

78 - 100 ______ 12 ______ 4 ______ 20

101 - 124 _____ 11 ______ 5 ______ 21

125 - 149 _____ 10 ______ 6 ______ 22

150 - 176 _____ 9 _______ 7 ______ 23

177 - 205 _____ 8 _______ 8 ______ 24

206 - 237 _____ 7 _______ 9 ______ 25

238 - 273 _____ 6 ______ 10 ______ 26

274 - 314 _____ 5 ______ 11 ______ 27

315 - 364 _____ 4 ______ 12 ______ 28

365 - 428 _____ 3 ______ 13 ______ 29

429 - 523 _____ 2 ______ 14 ______ 30

524 - 719 _____ 1 ______ 15 ______ 31

720 + _________ 0 ______ 16 ______ 32

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Rating Calculations [2100-2399]

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Rating_______HR(W)____Game___HR(L)

Difference____LR(L)____Drawn____LR(W)

0 - 10 ________ 12 ______ 0 ______ 12

11 - 32 _______ 11 ______ 1 ______ 13

33 - 54 _______ 11 ______ 2 ______ 14

55 - 77 _______ 10 ______ 3 ______ 14

78 - 100 ______ 9 _______ 3 ______ 15

101 - 124 _____ 8 _______ 4 ______ 16

125 - 149 _____ 8 _______ 5 ______ 17

150 - 176 _____ 7 _______ 5 ______ 17

177 - 205 _____ 6 _______ 6 ______ 18

206 - 237 _____ 5 _______ 7 ______ 19

238 - 273 _____ 5 _______ 8 ______ 20

274 - 314 _____ 4 _______ 8 ______ 20

315 - 364 _____ 3 _______ 9 ______ 21

365 - 428 _____ 3 ______ 10 ______ 22

429 - 523 _____ 2 ______ 11 ______ 23

524 - 719 _____ 1 ______ 11 ______ 23

720 + _________ 0 ______ 12 ______ 24

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Rating Calculations [2400+]

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Rating_______HR(W)____Game___HR(L)

Difference____LR(L)____Drawn____LR(W)

0 - 10 ________ 8 _______ 0 ______ 8

11 - 32 _______ 8 _______ 1 ______ 9

33 - 54 _______ 7 _______ 1 ______ 9

55 - 77 _______ 7 _______ 2 ______ 10

78 - 100 ______ 6 _______ 2 ______ 10

101 - 124 _____ 6 _______ 3 ______ 11

125 - 149 _____ 5 _______ 3 ______ 11

150 - 176 _____ 5 _______ 4 ______ 12

177 - 205 _____ 4 _______ 4 ______ 12

206 - 237 _____ 4 _______ 5 ______ 13

238 - 273 _____ 3 _______ 5 ______ 13

274 - 314 _____ 3 _______ 6 ______ 14

315 - 364 _____ 2 _______ 6 ______ 14

365 - 428 _____ 2 _______ 7 ______ 15

429 - 523 _____ 1 _______ 7 ______ 15

524 - 719 _____ 1 _______ 8 ______ 16

720 + _________ 0 _______ 8 ______ 16

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Assumptions

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These charts work on the assumption that decimals greater than or equal to .5 are rounded up in all circumstances.

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I am sure there are both mathematical

and grammatical mistakes. Please point

any out that you may find.

Hope you find this helpful,

Drew - 03 Jan '08 04:04

It could have been copied and pasted from somewhere, but who knows.*Originally posted by chesskid001***Wow, it must've taken forever to post that- Thanks for the info, I'll bookmark this page incase I ever need to refer to it again**

Anyway I have a question, how can you calculate your rating if you don't have a rating? - 03 Jan '08 07:27 / 1 editYour provisional rating will sort itself out as soon as you have completed 20 rated games. Looking at the opponent ratings in your graph I would expect your rating to come out somewhat higher than it is at present. In any case it takes quite a lot of games before your rating here will stabilise - and remember it's a correspondence chess rating, often quite different from your OTB rating.

And thanks again Drew for re-posting these charts; I keep a copy of one taped to my screen - and people think I'm clever because I can tell them how much it's going to cost them to lose this game ....