Poker Isolation Raise: GTO ISO Ranges, Sizing & When to Use It in 2026
An isolation raise is one of the most profitable plays against weak live players — and one of the most misused. Most players ISO raise too wide, size incorrectly, or do it from the wrong seat. This guide covers exactly when to isolate, which hands to use by position, and how to size for maximum fold equity.
What is an isolation raise in poker?
An isolation raise (ISO raise) is a raise made when one or more players have limped into the pot. You’re not just opening a fresh pot — you’re raising over weak money to get heads-up (or near-heads-up) against a limping range.
Example: Three players limp to you on the button. You raise to 15bb with K♦J♠. That’s an isolation raise. The goal is to fold the limpers, or at worst take the pot to the flop with a range advantage and position.
ISO raises differ from standard opens in one critical way: the pot already has dead money from the limpers. That changes your sizing math, your range, and your post-flop plan.
ISO raise vs. standard open vs. 3-bet
Why isolation raises are so profitable
Limpers are a gift. A player who limps preflop is almost always making a mistake — they’re entering the pot with a weak or passive range, giving up the initiative, and setting themselves up to play out of position with a capped hand. When you ISO raise, you exploit three things at once:
1. Dead money in the pot
Every limper adds 1bb to the pot before you act. With three limpers, you're raising into a pot that already has 4bb+ (limps plus blinds). Your raise is more profitable before a card is dealt — you're getting paid to fold them out.
2. Range advantage
Limping hands are typically weak broadway combos, small pairs, and speculative holdings. Against that range, your raise with hands like AJ, KQ, or 99+ has a massive equity edge. When limpers do continue, you're ahead of most of their range.
3. Position advantage
ISO raises from the BTN or CO put you in position post-flop against players who entered passively. A limper who calls your raise and then faces a continuation bet from a player who already showed strength is in a very uncomfortable spot.
When to ISO raise (and when to skip it)
Not every limped pot deserves an isolation raise. The value of an ISO depends on the number of limpers, your position, and how the limpers play post-flop.
Good ISO raise spots
- You have position (BTN or CO is best)
- 1-2 limpers with wide, passive ranges
- Limpers who fold to raises or play fit-or-fold
- Deep stacks (100bb+) where post-flop edge matters
- You have a strong or playable hand
Lower-value ISO spots
- × 4+ limpers (pot odds get cheap; you build a monster pot OOP)
- × Limpers who never fold (calling stations)
- × You’re out of position vs. multiple callers
- × Short stacks where SPR collapses post-flop
- × Weak speculative hands with no equity edge
The key variable most players ignore: what happens when they call? If a limper calls your ISO raise and then folds to any continuation bet, you print money with almost any two cards. If they call and then check-raise every flop they connect with, your ISO range needs to be tighter and your sizing needs to account for post-flop play.
Drill your ISO raise decisions until they’re automatic. Preflop Wizard presents real limped-pot scenarios with GTO feedback.
GTO ISO raise ranges by position
These ranges assume a 6-max cash game, 100bb effective, and one limper. Against multiple limpers, tighten each range by roughly one tier. Against limpers who never fold, shift toward pure value — cut most bluff candidates.
Button (BTN) ISO vs. 1 limper
~30-40% of handsValue / semi-value hands
AA-77, AKs-A2s, AKo-ATo, KQs-KTs, KQo, QJs-QTs, JTs
Bluff candidates
T9s, 98s, 87s, 76s, 65s, KJo, QJo
The button is the best ISO seat. You have position on every player who calls, and the limper's range is widest from early/middle positions. You can ISO almost your entire opening range here, including suited connectors and weak suited aces. Size to 4-5x (10-12bb vs. a 1bb limp).
Cutoff (CO) ISO vs. 1 limper
~22-28% of handsValue / semi-value hands
AA-88, AKs-A5s, AKo-AJo, KQs-KJs, QJs-QTs
Bluff candidates
JTs, T9s, 98s, A4s-A2s, KTo
Still a strong ISO position but the BTN has position on you post-flop. Keep your range slightly tighter than BTN. Speculative hands like 76s lose value because someone in position will see every flop with you. Size to 4-5x.
Hijack (HJ) ISO vs. 1 limper
~15-20% of handsValue / semi-value hands
AA-99, AKs-ATs, AKo-AQo, KQs-KJs, QJs
Bluff candidates
AJs (borderline), suited connectors (JTs, T9s only)
From HJ, multiple players have position on you when they call. Tighten significantly. Focus on strong one-pair+ holdings that play well in multi-way pots. Cut weak broadways and most suited connectors — their post-flop value drops when you're OOP to multiple callers.
Small Blind (SB) ISO vs. 1 limper
~18-25% of handsValue / semi-value hands
AA-88, AKs-ATs, AKo-AJo, KQs-KTs, QJs
Bluff candidates
A5s-A2s, KJs, suited connectors (JTs, T9s)
From the SB you're OOP to everyone except the BB, but you're also isolating with initiative. The SB ISO range is wider than you'd expect because you're building the pot with position advantage over the BB and equity edge over the limper. Size up to 5-6x from SB to charge callers properly.
Big Blind (BB) ISO vs. 1 limper
Raise to isolate: ~15% of handsValue / semi-value hands
AA-99, AKs-AQs, AKo-AQo, KQs
Bluff candidates
Limited — you're last to act, there's no squeeze dynamic, so bluffs here offer less fold equity
The BB ISO is the least common and least profitable spot. You check your option or raise for value/semi-bluff. Against a single limper from a late position, you can raise your premium hands and some suited connectors. But many BB spots are better handled with a call and post-flop play.
Adjusting for multiple limpers
Three limpers changes the math significantly. More dead money is good — but each additional caller reduces the probability your raise takes the pot preflop, and you’re likely to see a multi-way flop regardless of how you size.
| Limpers | BTN ISO size | Range adjustment |
|---|---|---|
| 1 limper | 4-5x open (9-12bb) | Full ISO range |
| 2 limpers | 5-6x open (12-15bb) | Drop weak suited connectors and offsuit bluffs |
| 3 limpers | 6-7x open (15-18bb) | Value-heavy — AA-JJ, AK-AQ, top suited connectors only |
| 4+ limpers | Consider calling or folding instead | ISO bluffs have almost no fold equity; size explosion creates awkward SPR |
Against 4+ limpers, many experienced players simply call in position with speculative hands or fold marginal ones. A massive ISO to 20bb from the BTN builds a huge pot with no initiative — if anyone calls (and at least one will), you’re playing a bloated pot with SPR under 4, which heavily favors set-mining limpers who already flopped well.
The exception: if you have AA or KK against 4 limpers, you still want to raise large to build the pot with your best hands. That’s not an ISO bluff — it’s a value construction.
Stop guessing in limped pots
Preflop Wizard quizzes you on real ISO raise situations — what to do, how to size, and why — with AI coaching on every decision.
How to size your isolation raise
ISO raise sizing follows a different rule than a standard preflop open raise. You’re not raising 2.5x into an empty pot — you’re raising over limpers who have already contributed dead money.
ISO raise sizing formula
Base open size (3bb) + 1 big blind per limper
Example: 1 limper — raise to 4bb. 2 limpers — raise to 5bb. 3 limpers — raise to 6bb. Add 1bb more from OOP positions.
| Situation | ISO Size | Why |
|---|---|---|
| IP, 1 limper | 4bb | Standard — enough to fold weaker limping hands |
| IP, 2 limpers | 5bb | Extra dead money justifies larger raise |
| IP, 3 limpers | 6-7bb | You need to price out everyone at once |
| OOP, 1 limper | 5bb | OOP tax — you need more fold equity to compensate |
| OOP, 2+ limpers | 7-9bb | Multi-way OOP is brutal; require them to pay heavily to continue |
Never min-raise a limped pot. A raise to 2bb over a 1bb limp gives every limper 4-to-1 odds to call. At those prices, even 72o starts becoming a call. You’ll build a massive multi-way pot with no fold equity, which negates the entire point of isolating.
Many live players also make the opposite mistake: over-sizing to 10-12bb against a single limper. Sizing this large forces limpers to fold even hands they should call with, which reduces the pot size when you’re winning and signals extreme strength. Limpers who hold monsters will call or reraise regardless — the extra sizing doesn’t protect you, it just builds a smaller pot when you take it down preflop.
The 4 most common ISO raise mistakes
1. Isolating from early position
UTG or UTG+1 ISO raises are almost never correct. You're out of position against every player at the table, and the BTN or CO will call in position and outplay you post-flop. From early position, most limped hands should be either opened or folded — not ISO'd.
2. ISO'ing calling stations
The entire math of an ISO raise depends on fold equity. Against a player who never folds, you lose the 'fold equity' component and you're just building a bigger pot in a spot where your edge is narrower. Against true calling stations, tighten your ISO range to hands that want to be called: AA-TT, AK-AQ, and strong suited hands.
3. Sizing too small with multiple limpers
Raising to 4bb over three limpers gives them roughly 5-to-1 on a call. At those odds, almost every limper continues — you've built a 15bb pot before the flop and you're likely playing a 4-way pot. Add the extra 1bb per limper so you're actually pricing some of them out.
4. Over-limping instead of ISO'ing
Many players see a limped pot and decide to limp behind with a hand like 87s or JTo instead of raising. This is almost always wrong. Limping behind with playable hands gives up initiative, builds a small pot, and puts you in a multi-way flop with no leverage. Raise or fold — don't over-limp.
Know exactly when to ISO and when to fold. Preflop Wizard trains GTO preflop decisions — including limped pots — in minutes a day.
How to respond when someone ISO raises you
If you limped and a player behind you raises, most hands should fold. You entered the pot passively with a weak-to-medium range — a raise from position over your limp usually has significant equity over your hand.
Fold
Default actionMost limping hands. 72o, 83s, K2o, J4s — fold. The pot is small, you're likely OOP, and your equity edge is slim.
Call
With suited hands / pairsPremium speculative hands with implied odds: TT-22 (set mining), suited aces (A2s-A9s), suited connectors (JTs, T9s, 98s). You need position or a strong draw to justify calling an ISO.
3-bet re-raise
Strong holdings onlyAA, KK, QQ, and sometimes AKs. When you limp-reraise, you represent extreme strength because the average limper almost never does this. The ISO raiser will often fold KQ-KJ and even JJ here. Use sparingly.
The limp-reraise is the most underused play at most live tables. Players who never reraise when they limp become predictable — an observant ISO raiser will just keep attacking their limps. Having AA or KK in your limp-call range at least occasionally prevents that. For more on 3-bet ranges and when to reraise, see the full 3-bet strategy guide.
ISO raises in tournaments
Isolation raises in tournament poker follow the same principles but with one major constraint: stack depth changes everything.
Stack depth rules for tournament ISO raises
Tournament antes add dead money that makes ISO raises more profitable at all stack depths. When the big blind ante is in play, a standard limped pot already has 2-3x more dead money than in a cash game — your ISO raise gets more fold equity from a larger starting pot. See the full MTT preflop strategy guide for stack-specific ranges.
Frequently asked questions
What is an isolation raise in poker?
An isolation raise (ISO raise) is a raise made over one or more limpers. The goal is to get heads-up against a weak limping range, build a pot with a range and position advantage, and win fold equity preflop. It's different from a standard open (no limpers) and a 3-bet (vs. a raiser).
How much should you raise to isolate a limper?
The standard ISO raise formula: base open size (3bb) + 1bb per limper. Against one limper, raise to 4bb. Against two limpers, raise to 5bb. Add 1 extra big blind when you're out of position. Never min-raise a limped pot — it gives everyone great odds to call and kills your fold equity.
What hands should you ISO raise with?
From the button against one limper, you can ISO raise roughly 30-40% of hands: all pairs (AA-77), strong aces (AK-AT offsuit, AK-A2 suited), strong broadways (KQ-KT suited, QJs), and suited connectors (JTs down to 65s). Tighten from earlier positions and against multiple limpers.
Should you ISO raise from early position?
Almost never. From UTG or UTG+1, an ISO raise leaves you out of position against every player at the table. The BTN and CO will call in position and outplay you post-flop. From early position, hands that are strong enough to raise should open normally, and hands not strong enough to open should fold.
Is it better to call or ISO raise in a limped pot?
Usually raise. Limping behind ('over-limping') with playable hands like 87s or JTo gives up initiative, builds a small pot, and creates a multi-way flop where your hand loses value. Raising takes control of the hand, charges worse hands to continue, and gives you a range advantage post-flop. The exception: rare cases where limping behind sets up a powerful limp-reraise trap.
How do you respond when someone ISO raises you?
Most limped hands should fold to an ISO raise — you entered passively with a weak range and the raiser has a significant equity edge. Call with premium speculative hands (small pairs for set mining, suited connectors with position). Consider a limp-reraise with AA, KK, or QQ to represent extreme strength — most ISO raisers will fold KQ-JJ to a limp-reraise.
Does the ISO raise strategy change in tournaments?
Yes, mainly because of stack depth. At 100bb, full ISO strategy applies. At 40-70bb, tighten your range and cut speculative hands — SPR shrinks and implied odds disappear. Under 20bb, skip ISO raises entirely and use push/fold strategy instead. Tournament antes add dead money that makes ISO raises more profitable per attempt, but stack depth is the primary constraint.
Related preflop strategy guides
Poker 3-Bet Strategy
When someone has already raised, this is your re-raise guide.
Preflop Raise Sizing
Open sizing, 3-bet sizing, and how to deviate from standard.
Button Strategy
The best seat for ISO raises — full BTN strategy guide.
Big Blind Defense
How to respond when someone ISO raises into your BB.
Cold Call Strategy
When calling is correct instead of raising or folding.
MTT Preflop Strategy
ISO raises, stack depth adjustments, and tournament ranges.