ICCF Elo rating calculator

This calculator is part of my C++ class library of chess rating systems. Please go to introduction page for further information.

ICCF is the official world correspondence chess federation with a pretty simple set of rating rules.

If you have less than 30 games, you must include all your games, not only the ones from the last period. Old rating is your initial rating.

ICCF Elo rating calculator 1

4 Responses

  1. Dear Ingram,
    your rating calculator is a very good idea, but you must take in account the concept of “maximum resistance”, which is fixed by ICCF in 350 points, if you want to give a proper answer in games between player with more than 350 rating difference.

    • I’m a bit puzzled about your comment, as I have implemented such a cut-off. It takes effect even in the calculation of the opponents’ mean where it is easy to notice. Can you provide me with a proper data set on which the calculator misses your expectation?

  2. Is this formula still active and conforms to the rating calculations used by ICCF? I compared a four game win streak between ratings calculators on USCF and your. USCF score new rating 160 points higher than your formula.

    • Apparently there is only a USCF rating calculator on the USCF website. While all these ratings are based on the same mathematical principles, the concrete formulae differ from one another.

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