A betting structure is the set of rules which control the amount a player can bet or raise in a poker game.
There are four types of betting structures for any poker game. The rules for them are somewhat detailed and are found in each of the separate articles on the structures, but the basics of each of the four are:
- Fixed-limit (sometimes just called Limit): the amount a player may bet or raise is limited to a single amount in any given betting round.
- Spread-limit: the amount a player may bet or raise is limited to a number within a certain range, or spread, for all betting rounds.
- Pot-limit: the amount a player may bet or raise is any amount between the minimum for the game and the amount which is already considered to be "in the pot". This can get very complicated to calculate; see the separate article on pot limit for details.
- No-limit: the amount a player may bet or raise is any amount between the minimum for the game and the amount of money they have currently on the table.
In any betting structure, a player who cannot make the minimum bet or raise required by the structure due to having insufficient chips (when they are playing table stakes) may always go all-in with their remaining chips.
Note that casinos may impose additional betting rules regardless of the choice of betting structure, either to comply with local laws (such as having a maximum total amount to bet, regardless of raises), or in the interests of the game (such as having a cap on the number of raises).
Any variant of poker may be played with any betting structure, but certain variants play better with certain betting structures, which lead to some traditional favorite combinations:
Hold 'em plays well with any betting structure, though it is most commonly found in no-limit and fixed-limit forms.
Omaha plays well in both fixed-limit and pot-limit forms, and is commonly found in both of those. Pot-limit Omaha is so common that it is often abbreviated as PLO.
7-Card Stud plays well in fixed-limit form.
Lowball or Razz both play well in fixed-limit and spread-limit form.