Limit
In limit poker, also called fixed-limit poker, the size of the raise a player makes is predetermined by the structure of the game or tournament. The structure will specify the size of the small bet, the large bet, the small and big blinds for games that use blinds, and the ante and bring-in for games that use them. It is typical in modern play for flop and draw variations to use blinds and for stud variations to use antes and a bring-in. Antes are almost never used in flop or draw variations played in either the limit or pot-limit format, but are commonly implemented in conjunction with the blinds in the no-limit format.
As an example, suppose you are playing limit holdem in a tournament at the 100/200 level. This means that the small blind is 50 (typically half the small bet), the large blind is 100, the small bet is also 100, and the large bet is 200. As this is a flop game, the small bet limit is used pre-flop and after the flop, and the large bet limit is used on the turn and river. In a game with only two rounds of action rather than four, such as California Lowball, the pre-draw action is at the small bet limit and the post-draw action at the large bet limit.
For a second example, suppose you are playing razz in a tournament at the 200/400 level with a 50 ante and a 75 bring-in. Each player will put in 50 before the first three cards are dealt and the player with the highest door card is forced to make a 75 bring-in, with an option to instead complete to 200, the full size of the small bet. The small bet of 200 is used for action on third and fourth streets (two rounds), while the large bet of 400 is used on fifth, sixth, and seventh street (three rounds of action). Most stud variations operate on this basis, with the bring-in being either the player with the highest or lowest door card, depending on the game.
An all-in wager of less than half the bet does not reopen the betting for a player that has already acted and is in the pot for all previous bets. A player facing less than half a bet may fold, call, or complete the bet. For example, suppose a player has made an all-in wager of 100 when the limit is 400. A subsequent player who has not yet acted may fold, call 100, or complete to 400. An all-in wager of a half bet or more is treated as as a full bet, and a player may fold, call, or make a full raise. For example, suppose a player has made an all-in wager of 300 when the limit is 400. A subsequent player wishing to raise would make it 300+400=700.
The number of raises that can be made per streeet varies between different poker rooms. Often a bet and 3 raises is allowed (i.e. it is possible to 4-bet but not to 5-bet); sometimes a bet and 4 raises is allowed. Often the cap on the number of raises is removed when two players are heads-up in a cash game, but typically not for a tournament. Check and raise is usually allowed, except in limit California Lowball.