Knowing what the bet rule is at your table is important as it can decide how you play. There are two types of bet rules: the full bet rule and the half bet rule. In this article, we will explain the difference between the two.
Pot-limit and no-limit games usually use full bet rule, while fixed-limit and spread-limit games may use either the full bet rule or the half bet rule.
The full bet rule states that if the amount of an all-in bet is less than the minimum bet, or if the amount of an all-in raise is less than the full amount of the previous raise, it does not constitute a “real” raise, and therefore does not reopen the betting action.
The half bet rule states that if an all-in bet or raise is equal to or larger than half the minimum amount, it does constitute a raise and reopens the action. For a better explanation, let’s consult Robert’s Rules of Poker:
In limit play, an all-in wager of less than half a bet does not reopen the betting for any player who has already acted and is in the pot for all previous bets. A player who has not yet acted (or had the betting reopened to him by another player’s action), facing an all-in wager of less than half a bet, may fold, call, or complete the wager. An all-in wager of a half a bet or more is treated as a full bet, and a player may fold, call, or make a full raise. (An example of a full raise on a $20 betting round is raising a $15 all-in bet to $35.) Multiple all-in wagers, each of an amount too small to individually qualify as a raise, still act as a raise and reopen the betting if the resulting wager size to a player qualifies as a raise.
Also, from Robert’s Rules is this qualification on multiple all-in bets:
Multiple all-in wagers, each of an amount too small to qualify as a raise, still act as a raise and reopen the betting if the resulting wager size to a player qualifies as a raise. Example: Player A bets $100 and Player B raises $100 more, making the total bet $200. If Player C goes all in for less than $300 total (not a full $100 raise), and Player A calls, then Player B has no option to raise again, because he wasn’t fully raised. (Player A could have raised, because Player B raised.)
You will encounter this often in a tournament situation when people become short stacked and all-ins are coming late in the game. When a player goes all-in and that bet is then called or raised, that money goes into the main pot. There is then an additional pot for betting between the players who were not all-in and have larger stacks. This is called a side pot. The player who went all-in will only be able to win the main pot while the other players can win both pots.
Additional Full/Half Bet Rule Questions: