Login to chess.com Start a game or open any game to see the score of the player on the top — like this one: https://www.chess.com/game/live/128552032877 If you meet a potential cheater (I consider 30%+ suspicious) — abort the game. Chess.com uses Glicko system for rating calculation, which determines your new rating (after playing a game) based on a couple of factors, including the amount of games you play and the difference between your and your opponent’s rating.