Answers.Body: <p>K-factor is used for each player individually. So, if one of them got 30 K-factor, his rating will change on the basis of that K-factor, while another player with 10 K-factor, for instance, will get rating on the basis of his own K-factor. </p>
  
  <p>There are Chess Rating Calculators on FIDE's official website. You can have a look: <a href="http://ratings.fide.com/calculators.phtml" rel="nofollow">FIDE Rating Change Calculators</a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-07T16:52:26.663Z
Answers.Text: If the two players have different K-factors, does this mean that the system is not a "pure" Elo system with an equal transaction of rating points?
Answers.UserDisplayName: wei
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Answers.Text: @wei, a pure Elo system can't have any new players entering the system, or any players stopping playing, so is not very usefull.
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Answers.UserDisplayName: Kanan Farzali
Body: <p><a href="http://en.wikipedia.org/wiki/Elo_rating_system#Most_accurate_K-factor" rel="nofollow">Apparently</a>, when calculating a player's USCF rating difference after a win or loss, the K factor that is used is based on the player's rating. Now, I was always under the impression that two players with ratings <code>a</code> and <code>b</code> would play each other and that a difference in score is awarded to both of them such that their ratings after the match would be <code>a+d</code> and <code>b-d</code> (assuming player A won the match).</p>
  
  <p>But let's say you have a player at 2075 (who would have a K factor of 32) and another player at 2125 (who would have a K factor of 24). Which K factor would be used? I could see a case for either of 32, 24, or even 28 being used in this case. What does USCF do here?</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-15T19:50:13.190Z
Comments.Text: I don't know USCF rules exactly, but if this turns out to be anything other than that each player is adjusted according to his own K-factor (so they get different changes) then I'd be amazed.
Comments.UserDisplayName: RemcoGerlich
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-16T01:19:13.577Z
Comments.Text: Wouldn't that mean that one player earns a different amount than the other player loses? I'd expect that to be an invariant.
Comments.UserDisplayName: corsiKa
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-16T21:21:46.453Z
Comments.Text: RemcoGerlich is correct, and yes, it does mean that.
Comments.UserDisplayName: dfan
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-17T03:43:03.510Z
Comments.Text: The USCF system described in the linked Wikipedia article is out of date. The K factor is no longer simply 16, 24, or 32 selected by a simple table lookup based on rating. It is now calculated based on the effective number of games played and number of games in the current event. Effective number of games is based on actual number of games and current rating. Full details here: http://glicko.net/ratings/rating.system.pdf
Comments.UserDisplayName: tzs
Tags: <elo><uscf>
Title: What K factor should be used if two players are in different K factor brackets?
ThreadText: # What K factor should be used if two players are in different K factor brackets?
  
  (Asked by: username_0 on 2013-12-15)
  
  [Apparently](http://en.wikipedia.org/wiki/Elo_rating_system#Most_accurate_K-factor), when calculating a player's USCF rating difference after a win or loss, the K factor that is used is based on the player's rating. Now, I was always under the impression that two players with ratings `a` and `b` would play each other and that a difference in score is awarded to both of them such that their ratings after the match would be `a+d` and `b-d` (assuming player A won the match).
  
  But let's say you have a player at 2075 (who would have a K factor of 32) and another player at 2125 (who would have a K factor of 24). Which K factor would be used? I could see a case for either of 32, 24, or even 28 being used in this case. What does USCF do here?
  
  **Tags:** elo, uscf
  
  > **Comments:**
  > **username_1**: I don't know USCF rules exactly, but if this turns out to be anything other than that each player is adjusted according to his own K-factor (so they get different changes) then I'd be amazed.  
  > **username_0**: Wouldn't that mean that one player earns a different amount than the other player loses? I'd expect that to be an invariant.  
  > **username_2**: username_1 is correct, and yes, it does mean that.  
  > **username_3**: The USCF system described in the linked Wikipedia article is out of date. The K factor is no longer simply 16, 24, or 32 selected by a simple table lookup based on rating. It is now calculated based on the effective number of games played and number of games in the current event. Effective number of games is based on actual number of games and current rating. Full details here: http://glicko.net/ratings/rating.system.pdf  
  
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  ## 1 answers
  
  ### Answer by username_4 on 2013-12-16. Score: 3 | Accepted answer
  
  K-factor is used for each player individually. So, if one of them got 30 K-factor, his rating will change on the basis of that K-factor, while another player with 10 K-factor, for instance, will get rating on the basis of his own K-factor.
  
  There are Chess Rating Calculators on FIDE's official website. You can have a look: [FIDE Rating Change Calculators](http://ratings.fide.com/calculators.phtml)
  
  > **Comments:**
  > **username_5**: If the two players have different K-factors, does this mean that the system is not a "pure" Elo system with an equal transaction of rating points?  
  > **username_6**: @username_5, a pure Elo system can't have any new players entering the system, or any players stopping playing, so is not very usefull.  
  
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