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Chris Hani Chess Association

Rating Calculator

Estimate a rating change before the event is published.

Your details

40 for a new player, 20 once established, 10 at 2400+.

Tournament results

Add each game you played.

Estimated new rating
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Enter your rating and games, then calculate.

How it works

The FIDE/CHC calculation

  • New rating = old rating + K-factor × (actual score − expected score).
  • Expected score = 1 / (1 + 10((opponent rating − your rating) / 400)).
  • The K-factor steps down as a player becomes established.
  • Win = 1 point, draw = 0.5, loss = 0.

This is an estimate only. Published ratings also apply a monthly cap and a rating floor, so the official change may differ.