What Is an Iso Raise? Isolation Raising in Poker

Six-handed cash game, 100bb stacks. A loose, passive player limps for 1bb in the hijack. The cutoff folds and you are on the button with K♠ T♠. The pot is 1 + 0.5 + 1 = 2.5bb.

The decision: raise to 4bb (3bb plus 1bb for the limper).

• Position: only the blinds act after you, and you will act last on every later street against the limper.
• Hand: K-T suited plays well heads-up against a wide limping range and can make strong flushes and straights if a blind also calls.
• The limper’s price: if the blinds fold, the limper calls 3bb more into a pot of 9.5bb after the call, about 32%. A min-raise to 2bb would ask only 1bb into 5.5bb, about 18%, inviting calls from the blinds as well.
• Fold equity is a bonus: you risk 4bb to win 2.5bb, so a pure steal needs folds 4 ÷ (2.5 + 4) = about 62% of the time. Loose limpers rarely fold that often. The profit comes after the flop, from position, the initiative and a better range.

The blinds fold and the limper calls. The pot is 4 + 4 + 0.5 + 1 = 9.5bb, with 96bb behind. The flop is T♦ 6♣ 2♥ and the limper checks. You have top pair with a king kicker, so bet about half the pot, 5bb. Weaker tens such as T-9 and T-8, any six and pocket pairs below ten can call, at a price of 5bb into 19.5bb, about 26%. A-T, two pair and sets beat you. If this passive player check-raises, they often have two pair or better.

An iso-raise works best when all three of these hold:

1. The limper plays too many hands passively. A player who limps often and rarely raises tends to call raises with weak hands and then fold or call too much after the flop.
2. You have position, or only the blinds are left to act. Raising from the cutoff or button means you play the hand in position. The poker positions guide and the position lesson explain why that matters.
3. Your hand plays well heads-up and holds up three-way. Iso-raises do not always isolate; a blind may call too. Pairs, suited broadway cards and suited aces work well. In late position you can add more suited connectors and strong offsuit broadway hands. See poker starting hands for the hand groups.

Overlimp or fold instead when:

• Several players have already limped and you hold a speculative hand such as 7-6 suited. Calling the limp gives a cheap multiway flop, which suits that hand.
• The limper limp-raises. Some players limp strong pairs to trap. Against them, raise only your strongest hands.
• Your hand is easily dominated. Weak offsuit hands such as K-9 or Q-8 often face a better kicker in a limper’s range and play badly when called.
• You are in the small blind with a speculative hand. You will play the rest of the hand out of position, so completing is often fine.

Iso-raises are larger than a normal open because the limper’s chip is already in the pot. A common starting point is 3bb plus 1bb for each limper in position, and about 1bb more out of position from the blinds:

Go bigger again against players who call almost any raise, which is common in live games: the goal is a heads-up pot against the weakest player, not a cheap multiway one. Go a little smaller when stacks are short, because a large raise commits too much of your stack.

After a call, the same table maths applies on every street: the caller needs call ÷ pot after the call. Run the numbers for any spot with the pot odds calculator, and check how your hand fares against a limping range with the equity calculator.

1. Min-raising over a limper. A small raise offers the limper and the blinds a cheap price, so you rarely isolate anyone.
2. Isolating with hands that play badly when called. Weak offsuit hands make second-best pairs and few strong draws.
3. Ignoring the players behind. An aggressive blind may squeeze, raising again over your iso-raise. The squeeze plays lesson covers that spot from the other side.
4. Auto-betting every flop after the call. Limpers who call raises also tend to call flop bets. Bet your value hands and real draws; check more of your complete misses.

What does “iso” mean in poker?

Iso is short for isolation. You raise to isolate one player, usually a limper, and play the hand heads-up against them.

Is an iso-raise a 3-bet?

No. A limp only calls the big blind, so the first raise over a limp is still the first raise of the hand, sometimes called a 2-bet. A 3-bet is a re-raise after someone has already raised; see the 3-betting lesson.

Should you ever just call behind a limper?

Yes. Overlimping is often fine with speculative hands behind several limpers, or against a player who limp-raises strong hands. It keeps the pot small and multiway, which suits small pairs and suited connectors.

Does iso-raising work in tournaments?

The idea is the same, but stacks are often shorter. Many players use smaller sizes, or move all in with short stacks rather than raise and fold. The poker strategy guide links cash and tournament topics. Sign in to open the full iso-raising lesson, with position-by-position ranges and practice decisions.