What Is a 3-Bet in Poker?

A 3-bet is the first re-raise of a betting round. Preflop the blinds count as bet one and the opening raise as bet two, so when you raise over that open you have made the third bet — the 3-bet. The same counting works after the flop, where a bet, a raise and then a re-raise gives you the postflop version.

How a 3-bet plays out

Blinds are $1/$2 in a 6-max cash game. The CO opens to $6, and you are on the BTN with A♠Q♠. You make it $18: the $2 big blind was bet one, the $6 open was bet two, your $18 is bet three. If the CO comes back over the top to $50 that is a 4-bet, and at 100bb the next raise is usually all in.

Two things happen at once. You build a pot with a hand that beats the range you are raising, and you take the initiative from the opener, who must now play the flop without the betting lead or out of position.

Sizing follows position, because position decides how much of your equity you actually realise.

Situation	Standard 3-bet	Why
In position, one raiser	3x the open	Position does part of the work, so you can charge less
From the blinds, out of position	4x the open	You are at a disadvantage all hand, so make continuing expensive
One or more cold callers	Add 1x per caller	Dead money in the middle widens what calls behind you

Which hands to 3-bet

The shape of your range depends on who opened.

• Against a loose open from the CO or BTN, go linear: JJ+, AQ+ and the strong suited broadways. These hands are simply better than what raised, and you want them heads-up in a big pot.
• Against a tight UTG open, go polarised: premiums for value, plus suited hands that flop well and fold cheaply. A5s and A4s are the standard bluffs because the ace blocks the hands that 4-bet you.
• Never 3-bet the middle, so AJo and KQo mostly call or fold against early-position opens. They are dominated by everything that continues and beat everything that folds.

The value half is easy. The bluffing half is where the money is won, and getting it right means knowing exactly which suited ace fires against which position. Sharkling's solver-built preflop charts give you that answer for every seat and every opener rather than a rule of thumb.

Facing a 3-bet

Folding everything but a premium is the most expensive habit in preflop poker. In the hand above, the CO faces a $12 call into a $27 pot — a shade better than 2 to 1, so around 31% equity breaks even, before you allow for the pots you lose out of position.

Split the response three ways. Call with hands that flop well and hold their value multiway, such as pocket pairs and suited connectors. 4-bet a mix of your best hands and a few blocker bluffs like A5s, so the 4-bet is not face up as KK+. Fold the dominated broadways, because calling a 3-bet with AJo out of position turns a decent hand into a guessing game for the next three streets.