Originally posted by Alopinto
I am 1586 and I am about to beat a 1820 opponent (OK, sorry about that ) How do I calculate my rating change?
You apply the values to this formula...
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)
Or you just read the next line...
1611. I have an excel spreadsheet to do it, but I know somebody wrote an online tool to work it out.