 # Rating calc formula JeremyDR Help 20 May '15 10:48
1. 20 May '15 10:48
in the FAQs the following is posted:
Players are rated using the following 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)

So win expectancy is >0 and <1 and k is >0 so together this implies that newscore>oldscore for a win.
I don't see therefore how score can decrease for a win...
Thanks
2. 20 May '15 12:36
Originally posted by JeremyDR
in the FAQs the following is posted:
Players are rated using the following 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 Expectanc ...[text shortened]... newscore>oldscore for a win.
I don't see therefore how score can decrease for a win...
Thanks
It can decrease at the setup of the first rating, which is kind of calculated retrospectively...since there was no (real) win expectancy.