*Originally posted by Invader*

**If you have less than 5 games, no. Otherwise I have attepted the math:
**

K=32

Old Rating=1200

Score = .5

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/200)+1)

= 1 / (10^((1200-1200/200)+1)

= 1 / (10^1)

= 1 / 10

= .1

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

...[text shortened]... 0 + 32 * (.5 - .1)

= 1200 + 32 * .4

= 1200 + 12.8

= 1213

The win expectancy formula is used when you have played more than 20 games (your rating isn't provisional anymore).

Until you complete 20 games (and you've completed more than 5) your rating is the average of all your game values.

The game value is your opponent's rating + 400 if you win , -400 if you lose. It's equal to your opponent's rating if you draw.

If your opponent is provisional the 400s are 200s.

Therefore if two p1200's play each other and draw no change is made to their ratings.