As a player who has not yet played online chess at this site I would like a

simple explanation as to how rating assessments are calculated.I have

scrutinised online match results and am confused as to how the ratings are

calculated.I understand that  unrated matches are not affected by win/lose

results.It appears that on some occasions (in rated matches)draconian points

are deducted from the losing players tally whereas in some similar cases

the losing player forfeits few points.

It would apear that in practice a player might achieve a zero rating

if he or she were to lose a number of matches to a "weaker" player.

Is there any way that rating adjustments can be made to avoid

large rating reductions upon a lost match.

I have seen your columns of explanation of rating assessments but it

is rather complicated.

Any "simple" explanation would be appreciated.

I send greetings to all members of this chess "club"!

Put simply, there's two main things that affect how much a rating changes.  The first is how much of a difference there is between the two players' ratings.  Beating someone rated far below you will give you fewer points than beating someone of your own rating.  Similarly, beating someone with a much higher rating will give you even more points than that.

The second thing is something called RD (Rating Deviation).  Put simply, that number is a measure of how accurate the rating is.  If you have a large RD, then your rating isn't very accurate - maybe you haven't played in a while or have performed counter to what your rating would indicate (beating someone higher rated or losing to lower rated players).  If this is the case, then larger changes are to be expected - to try to get your rating more accurate more quickly.  On the other hand, if your opponent has a large RD, then your rating won't change as much.  After all, if the site isn't really sure about your opponent's rating, then your shouldn't be punished for an unexpected loss or unduly rewarded for an unexpected win.

So, the actual change of rating is based not only on the result of the game, but also your rating, your opponent's rating, your RD, and your opponent's RD.

Please quanitify how much my rating will go up or down based on the rating of my opponent.