Chess Ratings

See it in action

The development team where I work will soon be celebrating the launch of our new company website a good old fashioned chess tournament. Now, like any good development team, we have our fair share of geeks; geeks with interests in a wide variety of geekery. One such geek is a big fan of fantasy sports, so we tasked him with organizing said tournament. As a result, we will be doing a round-robin tournament to establish a relative ELO rating for each player, then use these ratings to seed a double elimination bracket tournament (I’m about 60% sure I got the names right for all that stuff). Anyway, the key component for the round robin is having a method to establish our ratings.

The ELO rating system is the most widely used in the chess world, and with good reason. When you have a sport played by some of the greatest minds in the world, it only makes sense to have an overly complex and highly accurate way of showing relative strength. In fact, it’s so impressive that just about nobody outside of official chess organizations actually does it properly. The rest of the world kind estimates an ELO, or approximates it. I am happy to be one of those folks.

I have neither the time nor the care to implement a 100% accurate chess rating system. All I need for the tournament is something that works decently well. So, I built it!

My chess ratings page allows you to enter the starting rating for each player, pick the outcome of the game, and it will show you the new ratings. How do I do this? Well, I use a formula I lifted from! I didn’t steal their code or anything. I just followed the instructions on their FAQ (mostly).

Why don’t you go try it out! And if you’re interested in my algorithms and junk, here’s the main code.

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