Isolation Raise (Iso-Raise) in Poker

Last updated: May 12, 2026

An isolation raise (iso-raise) is a raise over a limper designed to get heads-up against a weaker player, denying other players favourable odds to enter the pot.

Standard iso-sizing is 3–4bb + 1bb per limper — so vs one limper raise to 4–5bb, vs two limpers raise to 5–6bb. From the BTN you can iso wider (top 35–40% of hands) vs EP limpers; from UTG stay tight with around 5–8%.

This page covers iso-raise sizing by position and limper count, which hands to iso with, adjustments for multiway spots, and how to play postflop after isolating. Playing heads-up in position against a recreational player adds a 30–40% win rate edge compared to multiway pots.

What Is an Isolation Raise?

When one or more players limp into the pot (call the big blind rather than raise), skilled players often re-open the action with a larger raise. This is called an isolation raise. The mechanics are simple: by raising to a size that is unprofitable for other players to call, you thin the field and aim to play a heads-up pot against the limper — typically a recreational player.

The name "isolation" comes from the goal: isolate the weak player away from the rest of the table. Limping is a leak in modern poker — it does not take initiative, does not build equity, and signals a passive range. Against passive limpers, a well-sized iso-raise accomplishes three things:

Collects dead money from players who fold (blinds, other limpers)

Denies players yet to act their favourable implied odds to enter cheaply

Sets you up to play postflop in position with range advantage

See also: limping and over-limping — why limping is generally a weaker line and when it occasionally has merit.

Iso-Raise Sizing — Position and Limper Count

The formula is straightforward: start with 3–4bb and add 1bb for each limper already in the pot. The lower end (3bb base) works when you are in position and the field is tight; the higher end (4bb base) is appropriate when playing live with passive calling stations or when you need to deter multiway callers.

Base sizing: 3–4bb
+ 1bb per limper already in the pot

vs 1 limper → raise to 4–5bb
vs 2 limpers → raise to 5–6bb
vs 3 limpers → raise to 6–7bb

BTN vs 1 EP limper

4–5bb

Position is strong; 3bb base + 1bb for limper. Lean toward 4bb total.

CO vs 2 limpers

5–6bb

3bb base + 2bb for limpers. Discourages the whole table from calling.

UTG+1 vs 1 limper

4–5bb

Same formula but choose hands tightly — you are often OOP postflop.

SB vs 2 limpers

6–8bb

SB will be OOP vs all streets. Size up significantly; fold equity is critical.

Which Hands to Iso With (Position-Based)

Position is the dominant factor in iso-raise range construction. The later you act preflop, the more hands you can profitably iso with — you will be in position more often postflop and can realize your equity more efficiently. For a deeper look at why position matters so much, see positional advantage.

UTG

Tight

5–8%

TT+, AJs+, KQs

Moderate

20–25%

66+, ATs+, KJs+, QJs

BTN

Wide

35–40%

All pairs, broadways, suited connectors

Selective

15–20%

88+, AJs+, KQs, QJs

These ranges assume a single passive limper with no players left to act behind who are likely to squeeze. Tighten when facing a limper known to limp-reraise (a strong trap play) or when multiple competent players remain to act. For the full framework see poker hand ranges.

SB Special Case

The SB iso range (15–20%) is narrower than the BTN despite acting last preflop in one sense — the SB is out of position vs every other player postflop. Only iso from SB with hands that play well OOP: strong broadways (AQs+, KQs), mid-to-high pairs (88+), and a few premium suited connectors.

Iso-Raising vs Over-Limping — When to Choose

Over-limping (calling the limper's limp) is occasionally correct with hands that need multiway implied odds to be profitable — small pocket pairs and suited connectors in very deep-stacked, passive games. But as a default, iso-raising is almost always superior. Here's when each approach makes sense:

Iso-Raise When

+You will be in position postflop
+Limper is recreational or passive
+You have a hand that plays well heads-up
+Field behind you is tight or likely to fold
+Stack depth is 40–150bb (standard)

Over-Limp When

–Very deep-stacked (200bb+) with small pairs or SCs
–Multiple recreational players already in the pot
–Likely to face a squeeze from a strong player behind
–In the BB facing multiway action (check is better)
–Limper is known to limp-reraise (trap hand)

Playing Postflop After Isolating

After a successful iso-raise you are heads-up in position with range advantage on most board textures. The preflop raiser's range skews toward high cards and pairs; the limper's range is wide and capped — they rarely have AA or KK (most players raise those preflop). This gives you the following postflop advantages:

C-bet frequency

Bet 60–75% of flops in position vs a single recreational player. They call too wide and fold too infrequently to bluffs, so lean toward thinly-valuebet hands rather than pure bluffs on scary boards.

Board texture

On A-high boards you have a large nut advantage — bet most of your range. On low, connected boards (7-6-5 type) the recreational player's limping range connects better; check back medium pairs and wait for better spots.

Pot control

Against calling stations, avoid bloating the pot without the nuts. Check back top pair mediocre kicker on wet boards. Your edge comes from volume over many streets, not a single huge bet.

Exploiting passivity

Recreational players check-call rather than check-raise. When they check-raise, they almost always have it. Fold your bluffs and continue with strong value hands only.

When Iso-Raises Fail (Multiway Pots)

Even well-sized iso-raises get called by multiple players in passive live games. When two or more players call your iso, the dynamic changes completely. Many hands in your iso range that were strong heads-up become marginal or losing in multiway pots.

Multiway Adjustments

·Cut c-bet frequency to 30–45% — check back more hands on all board textures
·Only barrel with strong made hands or draws that have good equity even if called
·Suited connectors and small pairs gain value (set/flush mining in multiway pots)
·Bluffs lose most of their EV — fold equity drops sharply with multiple callers
·Size bets larger (60–80% pot) to charge draws from multiple players simultaneously

If multiway pots are a persistent problem (e.g., very loose passive tables), increase your iso sizing to 5–6bb base. In extreme cases, consider not iso-raising marginal hands at all — wait for premium holdings that are strong even multiway. See cold calling vs raising for when flatting instead of iso-raising can be correct.

Exploiting Recreational Players with Iso-Raises

The iso-raise is fundamentally a player selection tool. The goal is not simply to raise — it is to manufacture as many heads-up pots as possible against the weakest player at the table. Research and practical results consistently show a 30–40% win rate improvement when playing heads-up in position against a recreational player vs a multiway pot with the same hand.

50–70%+

Target limper VPIP

Recreational players voluntarily put money in the pot far too often

30–40%

Win rate boost (HU IP)

Heads-up in position vs recreational vs multiway spotted

80–90%

Optimal iso frequency

Of hands in range vs single recreational limper from LP

100bb

Live stack depth

At which iso-raising is most straightforwardly profitable

Seat selection matters too: sit to the left of the recreational player so you have position on them most often. When combined with iso-raises, consistent positional advantage over a weak player is one of the highest-EV adjustments in live poker. See also preflop opening ranges and poker hand ranges for building a complete preflop framework.

Definitions

Isolation Raise (Iso-Raise)

A raise made over one or more limpers with the intent to play heads-up against a weaker player. Standard sizing is 3–4bb + 1bb per limper. The raise prices out other players and ensures positional advantage against the target.

Limper

A player who enters the pot preflop by calling the big blind rather than raising. Limping is generally considered a weak play in modern poker because it does not build the pot, does not take initiative, and invites multiway action.

Dead Money

Chips already in the pot from players who will not win the hand — typically blinds or folds. When you iso-raise, the limper's chips become dead money if they fold, and the blinds' chips add to your expected profit.

Recreational Player

A non-professional poker player, also called a 'fish' or 'whale', who plays loosely, calls too wide, and makes systematic strategic errors. Iso-raising is specifically designed to exploit recreational players by getting heads-up against them.

Heads-Up Pot

A pot contested between exactly two players. Heads-up pots are more profitable for skilled players because bluffs are more effective, thin value bets win more often, and pot control is easier than in multiway pots.

Range Advantage

When your overall range of hands is stronger than your opponent's on a given board texture. After an iso-raise, the preflop raiser typically holds range advantage on most flop textures, which justifies frequent c-betting and applying pressure.

Frequently Asked Questions

What is an isolation raise in poker?

An isolation raise (iso-raise) is a raise made over one or more limpers with the goal of getting heads-up against a weaker player. By raising, you price out other players and deny them favourable odds to enter, while also building a pot you intend to play in position against a recreational opponent. The term 'isolation' refers to isolating the limper away from the rest of the table.

How do you size an isolation raise?

The standard formula is 3–4bb plus 1bb per limper already in the pot. Against one limper, raise to 4–5bb. Against two limpers, raise to 5–6bb. From the button you can lean toward the lower end because position adds value; from early position, use the larger end of the range to compensate for playing out of position postflop. In live games with passive fields, some players size to 5–6bb + 1bb per limper to better charge drawing hands.

What hands should you isolation raise with?

It depends on position. From the button you can iso with the top 35–40% of hands — all pocket pairs, all broadways, suited connectors, and many suited one-gappers. From UTG, tighten to roughly 5–8%: TT+, AJs+, KQs. The key criterion is that your hand plays well heads-up in position and has strong value vs a loose limper's range. Avoid iso-raising speculative hands like 54s or small pairs from early position where you will often be out of position postflop.

Is it worth iso-raising from early position?

Generally only with a strong, narrow range (TT+, AJs+, KQs — roughly 5–8% of hands). From UTG or UTG+1 you will frequently be out of position against the limper and face multiway action from players left to act. The EV advantage of isolating shrinks substantially when you are OOP postflop. If the limper is in the BB or SB and you are in LP, the iso is much more clearly profitable.

What happens when your iso-raise gets called by multiple players?

You are now in a multiway pot, which significantly reduces the profitability of many hands in your iso range. Speculative hands (suited connectors, small pairs) gain value in multiway spots, while bluff-heavy or thin-value holdings lose equity. You should tighten your c-bet frequency dramatically — barrel only on boards that strongly favour your range — and lean toward checking and pot control with medium-strength hands.

How is an iso-raise different from a standard open raise?

An open raise is made when no one has entered the pot voluntarily — you are first in. An iso-raise is made after one or more players have already limped in. The sizing is larger (adding 1bb per limper), the intent is explicitly to thin the field to heads-up, and the target is a specific weak player rather than simply stealing the blinds. An open raise is about initiative; an iso-raise is about player selection and heads-up edge.