A 4-bet is a re-raise over a 3-bet. Before the flop, the order is: big blind (1st bet), open raise (2nd), 3-bet (3rd), 4-bet (4th). A raise over the 4-bet is a 5-bet, which in most games means all-in.
A 4-bet example
You open to $6 at $1/$2 with K♠ K♣. The button 3-bets to $18. You re-raise to $45. That re-raise is a 4-bet.
How big should a 4-bet be?
- In position: about 2.2 to 2.5 times the 3-bet.
- Out of position: about 2.5 to 3 times the 3-bet.
- With 40 big blinds or less behind, a 4-bet commits you to the pot, so it is usually better simply to go all-in.
Which hands should you 4-bet?
Value 4-bets are the very top of your range: AA, KK and usually QQ and AK. In solid online games, players add a few bluffs with hands like A5 suited, because the ace blocks the opponent from holding AA or AK. In most live games, 3-bet ranges are tight and players rarely fold to a 4-bet, so 4-betting for value only is the simpler and more profitable choice.
How to respond to a 4-bet
A 4-bet usually represents a very strong range. Against unknown players, fold most hands, call with hands that play well in big pots, and get all-in with AA and KK. The poker odds calculator shows how your hand does against a tight range such as QQ+ and AK.
Every term in this series is listed in our poker glossary.