user18844: I have a Chess.com tactics rating (default blitz setting where time to solve is instrumental in getting points)  hovering around 1750 but for some reason I can't get beyond 1550 on the Chess Tempo's Chess-Tactics site on the standard rating scale (no time limit). Any reason why?  Is it only because the blitz capability and the no-time-limit capability are different, or because the problem difficulty ratings in these two websites are different?

user18809: Different sites will have different rating systems, even for games!
So, for tactical puzzles, basically every site works in a completely different manner. Also, I don't know about chess.com, but in chesstempo, different settings will also result in different ratings, as the kind of puzzles will be different, and the balance is not perfectly achieved.

18844: <p>I have a Chess.com tactics rating (default blitz setting where time to solve is instrumental in getting points)  hovering around 1750 but for some reason I can't get beyond 1550 on the Chess Tempo's Chess-Tactics site on the standard rating scale (no time limit). Any reason why?  Is it only because the blitz capability and the no-time-limit capability are different, or because the problem difficulty ratings in these two websites are different?</p>
 18809: <p>Different sites will have different rating systems, even for games!</p>

<p>So, for tactical puzzles, basically every site works in a completely different manner. Also, I don't know about chess.com, but in chesstempo, different settings will also result in different ratings, as the kind of puzzles will be different, and the balance is not perfectly achieved.</p>
