Fixed-limit (also called just Limit) is a type of betting structure for a poker game where the amount of all bets and raises in any given betting round is fixed. This is in contrast to pot-limit and no-limit betting.
Most commonly, fixed-limit games have two bet sizes, called the small bet and the big bet. Such games are usually written as having limits of "small-slash-big". For instance, a game where the small bet is $2 and the big bet is $4 would be called a "2/4" game. A game where the small bet is 20 and the big bet is 40 is written as "20/40".
In Hold 'em and Omaha, there are four betting rounds: preflop, flop, turn, and river. If a game with four betting rounds is structured as fixed-limit with two bet sizes, the small bet size refers to the betting preflop and on the flop, while the big bet size refers to the betting on the turn and river.
In 7-Stud and Razz, there are five betting rounds (after streets 3 through 7). If a game with five betting rounds is structured as fixed-limit with two bet sizes, the small bet size refers to the betting in the first two betting rounds while the big bet size refers to the betting on the final three rounds.
More than two bet sizes
Fixed-limit games are not necessarily structured with only two bet sizes, however. If they are not, then the structure is described with all the betting round limits spelled out with slashes between the numbers.
For example, a Hold 'em game has four betting rounds, so a fixed-limit betting structure might be written as "1/4/8/8", which would mean the betting sizes are fixed at $1 preflop, at $4 on the flop, and at $8 on the turn and river. A "1/1/3/3/6" game of Razz would use $1 limits on the deal and on fourth street, $3 limits after the fifth and sixth cards, and $6 limits on the final card's betting round.
If a fixed-limit game is written as only two numbers with a slash between them, it is always interpreted as a two-bet-size fixed-limit game as described in the section above; otherwise, all the betting limits for the various rounds are spelled out explicitly.
A player in a fixed-limit game may choose to bet or raise when it is their turn to take a betting action. When they do so, they may only do so in the amount of the fixed limit for this betting round. If they do not have enough chips to take their intended action, they may go all-in for their remaining chips.
For example, in a 4/8 game of hold 'em, Player A has $20 in chips and Player B has $60. Player A picks up pocket aces and wants to bet. Player A may only bet $4 even if they would like to shove in their entire $20. Player B may then decide to fold, call the $4 or raise -- and if Player B raises, they may only raise an additional $4, making it a total of $8. If the actions comes around to Player A again, they may re-raise (assuming no house rule of casino forbids it), but again may only do so for $4, making it $12 total.
Assume in our example that Player B merely calls the extra $4, and on the flop Player A again bets out; again, they may only bet $4 on the flop. Player B also calls. The pot now contains $32 (assuming no other players are in) and Player A has only $4 remaining on the table. On the turn, Player A would like to bet again, but in this round the required minimum bet is $8, and Player A only has $4 left. At this point, Player A may go all-in for their remaining $4, despite the fact that they do not have enough chips to make the minimum bet.
In fixed-limit, there are really only five choices available to a player when it is their turn to make a betting action: check, bet, fold, call, or raise. The amounts by which they can bet or raise are fixed, so there is much less decision-making to be done by players. In theory, this speeds up the game; in practice, it doesn't seem to help that much.
In fixed-limit games, an all-in player often cannot make the correct fixed amount for a bet when they go all-in (since that amount is fixed, they would have to have exactly the right number of chips left to match the fixed limit, which is not particularly likely, though certainly possible). This results in the all-in player betting a legal partial bet into the pot, a bet which does not conform to the required fixed limit.
When that happens, players who come after the all-in player may choose to call the partial bet, even though it would not normally be an allowable amount to have bet. Later players may also choose to raise the all-in player (thus creating a side pot). If they do so, one of two things happens, depending on the size of the all-in player's partial bet:
- If the all-in player's partial bet was less than half of the required fixed limit, the subsequent player who wants to raise may only complete the bet by raising enough to make the amount bet match the required fixed limit. For example, when a player goes all in for $2 into an $8 betting round, a subsequent player who wishes to raise may only complete the bet to $8 by placing a total of $8 in front of them, which is the equivalent of "raising" the all-in player by an additional $6.
- If the all-in player's partial bet was half or more of the required fixed limit, the subsequent player who wishes to raise may do so by raising a full fixed limit amount over the all-in player's partial bet. For example, when a player goes all in for $6 into an $8 betting round, a subsequent player who wishes to raise may only raise it to a total of $14 (raising the $6 by an additional $8).
Note that these rules may be altered slightly by individual casinos, but are considered to be standard poker rules and would be found in nearly all poker rooms.