There is no simple formula that will give you an exact figure of a game’s profitability in relation to the rake or time charges. There are some things to consider however, that should allow you to make an educated decision on whether to play in a given game. You must consider the cost and how it is collected from the players, as well as the players and how much of a favorite to beat them that you are. Also, you must consider the action at the table and average pot size in relation to the charge and how it is collected.
First off, time charges are going to be better than rakes in most cases, but possibly not all (if the time was really high this might not be true). I have never seen a game with a time charge that I wished had a rake, in my experience it is always cheaper to pay time than rake. I play low limits in a casino where the time charge on 3-6 kill Holdem is 3$/half hour. That is a fantastic deal and is the lowest cost I have seen anywhere. On 4-8 kill the time is 4$/half hour. That is still well within the limits of beatability, and it is still cheaper than most raked games by a significant margin. The 8-16 game also has a 4$/half time charge, making it the best deal in the house, costing you only 1 small bet per hour. Not too shabby. This is the primary reason why I play almost exclusively in this cardroom, the other choices I have are all dropped games and are considerably more expensive. Time charges hurt all players equally whether they are loose or tight.
If the game is raked, you are probably paying quite a bit more …