Chess Rating Change Calculator

After a tournament or a batch of rated games, you want to know how much your chess rating will move, and this calculator estimates it the way rating systems do. Enter your current rating and your K factor, then list your opponents ratings and the result against each one as a win, draw, or loss. The tool computes your expected score against every opponent using the logistic Elo formula, sums the expected total, compares it to your actual score, and multiplies the difference by K to give your net rating change and your new estimated rating. It also shows your tournament performance rating, a snapshot of how strong you played based on results and opposition. This is a great sanity check before the official rating update posts. Everything runs locally in your browser with nothing sent to a server, so paste in a full event and see the swing before it becomes official.