printf(“Hello everyone\n”) ;

Today I want to present my program (written in C++ language with Qt) which calculates rating change (Elo system, used in chess ratings by FIDE).

I know chess players shouldn’t put too much attention to their ratings, especially during a tournament but still, just in case somebody is curious about his or her rating change and don’t know how to calculate it – here is the perfect solution!

The program is user friendly and I don’t think I need to explain how to use it, just a quick view how it looks like:

rating change calculator

rating change calculator by piongu

Choose ratings and select correct result and ‘k’ (the development coefficient) and press calculate button. You’ll see another window with the result.


K = 30 for a player new to the rating list until he has completed events with a total of at least 30 games.
K = 15 as long as a player`s rating remains under 2400.
K = 10 once a player`s published rating has reached 2400, and he has also completed events with a total of at least 30 games. Thereafter it remains permanently at 10.

How to get it?

The program is open source (GPL license) and absolutely free of charge, just some feedback are welcome.

  • for Windows users (majority of my readers as I expect): download .zip file, unzip and run .exe file. No installation is needed! (if you are more ambitious Windows user, you can use source given below and compile it using for example QtCreator)

for Mac OS users – I think u are rich enough to buy such a product

This is the first version of my program, at the moment you can’t calculate rating change from the whole tournament at once. This is the thing I’ll work on till the second version which will be released when I’ll have time to do it 😛 In addition I expect to add feature to rating performance

I’d be very grateful if you say whether you like my program or not, and what you expect in version 2. Feel free to comment!