ICM Calculators and Super Short-Stack Tournament Strategy

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Arved Klöhn Pokerlistings Author
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  • Last updated on: January 14, 2025

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This week CardRunners coach Samer “Braminc” Khuri explains ICM calculators and how fully understanding them can help us with super short-stack poker tournament strategy.

Samer “Braminc” Khuri has been playing SNGs full time since 2006. He plays a wide range of stakes and his latest CardRunners video series, SNG Payout Analysis, explains how to effectively adjust to any tournament structure in the world. In his spare time he plays guitar, sings, and writes music.

Take it away Samer.

Most people that play poker tournaments are familiar with one very basic and crucial concept: When your stack reaches a certain critically low level, you must either go all-in or fold pre-flop.

Raising a standard amount becomes suboptimal, as you will end up having less fold equity yet still be committed to the pot after the flop (no matter what the flop is).

The idea is to maximize our fold equity while we have it to increase our chances of survival.

What Exactly is “Critically Low” in Poker?

While this is widely accepted, there is some debate as to just how short stacked “critically low” is. Some players seem to only shove/fold when their stack reaches 15 big blinds or less. Some say 10 big blinds or less.

Some point out that you should calculate your M—your stack size divided by the total value of the blinds and antes—and shove whenever M is less than 10. None of these answers is exactly right or wrong. It depends on the tendencies of your opponents, how they view a pre-flop shove from you, and how they react to a standard raise from you.
10 big blinds and an M of 10 have always been key values for me. There are absolutely times when I will shove 15 or even 20 big blinds, and there are other times when I will make a standard raise with as few as 8 big blinds. Both of those scenarios are rare, and they are not what this article is about.

I want to discuss the shortest of short stacks: the times you have 5 big blinds or less (or an M of 5 or less). In these situations, you are running out of fold equity. You need to move quickly. To play online poker cautiously at this stage will lose you money in the long run.

Many of us use ICM calculators to determine what hands are +EV to shove in what spots (and what hands aren’t). These ICM calculators are the key to short stack tournament poker. However, they have limitations.

What is ICM?

ICM is a measurement of total prize pool equity. Using it, you can compare the value of your stack if you move in and if you fold. The first problem we encounter is that your prize pool equity is based solely on the number of chips you have now relative to the total number of chips and players remaining. No account is taken of the players’ skill.

The calculator doesn’t know how good you are; even we humans don’t know exactly how good anyone is. So, if you are one of the best players at the table, ICM is likely to underestimate the value of your stack; this will affect the best play sometimes. Another major limitation of ICM, and the most relevant one to this article, is that because these calculators simply compare your prize pool equity if you shove or fold immediately after the hand, they ignore future hands.

Another way to put this point is that the real value of your stack can depend on the position of the blinds, whether you are likely to be in very bad situations soon, and so on.

Take Shoves That Are -EV

In my view, when you are as short as 4 or 5 big blinds, you need to take shoves that ICM says are –EV, because folding is often even worse than ICM indicates. The problem is that calculating just how bad our future situations will be can be extremely difficult. Nobody can figure this out with complete accuracy; it depends on all our opponents’ tendencies and is sensitive to very small changes in their stack sizes.

Usually we will not be dealt monster cards within the next orbit of play, and since our fold equity will disappear when we continue folding, we will be getting our chips all-in as huge underdogs a majority of the time. After studying hundreds of short-stack tournament scenarios, I can confidently say that the degree to which we should be willing to take -EV shoves at 4-5 big blinds is much higher than I ever would have expected.

In a typical SNG, -1% to -2% of the prize pool is an extremely reasonable -EV shove to make under the gun when facing the alternative of blinding out of play. In larger tournaments the same is true, although the exact number will be different because of the greater field size.
If you are able to fully understand what ICM is, how it works, and what the ICM calculators are telling you, then you can apply good reasoning to learn when it is appropriate to deviate from their suggestions.

The Tournament Must Continue

In this case, we have observed that ICM calculators are unaware that the tournament doesn’t end after the exact hand it is analyzing. Because the tournament must continue, folding trashy cards with a stack of 4 or 5 big blinds can be pure suicide as you will soon have literally zero fold equity and close to zero prize pool equity. We must do our best to estimate which -EV shoves are appropriate and which aren’t. The short answer is that almost all -EV shoves in the described situation are very appropriate and necessary.

Advanced Short-Stack Concepts

Many experienced players incorporate more advanced methodologies when dealing with super short stacks. While ICM provides a useful snapshot, deeper considerations, such as how quickly the blinds escalate or where stronger players act behind you, can significantly affect your ranges.

Incorporating Opponents’ Tendencies and Future Game Simulation

When blinds move quickly, and you expect to face strong players, it can be important to adjust your push-fold strategy to account for these dynamics. Some professionals use future game simulations to anticipate how the next few hands might evolve, rather than relying solely on the static view of a single hand. Such simulations can help you see whether you’ll likely face multiple resteal threats, whether tight opponents will fold too often, or whether aggressive players will exploit your reluctance to shove. Understanding these factors in the context of your ICM-based decisions can be the difference between an early exit and a deep run.

Future game simulation can also guide how you handle borderline situations where typical ICM calculations might suggest a fold, yet the reality of pending blinds and possible triple-barrel aggression from skilled players might alter the math. Seeing just a few hands ahead can refine your push ranges and help you preserve chips and fold equity.

Exploitative Adjustments vs. GTO Solutions

A purely GTO strategy might call for precise push-fold decisions based on combined frequencies and ranges, but poker tournaments are rarely static or purely theoretical. If you have reason to believe your opponents are calling too tightly, you can expand your pushing ranges significantly when super short. Conversely, if players behind you are loose and willing to call with marginal hands, you might tighten your ranges more than ICM alone would suggest. Balancing a GTO-based approach with exploitative observations ensures that you capture maximum equity, even when the numbers look initially unfavorable.

FAQ

What is ICM?

ICM stands for Independent Chip Model, a method used to measure each player’s share of the prize pool based on stack sizes. It helps compare the equity gain or loss of decisions such as shoving or folding in tournament play.

Why do I need to push with hands that might be -EV according to ICM?

At super short stacks, folding leaves you with even less fold equity in future hands. Often, the long-term cost of waiting for a better spot can be greater than taking a slightly -EV shove.

How do I handle weaker holdings when I have only 5 big blinds left?

You should consider that many future deals will be even worse, both in terms of hand quality and position. If an ICM calculator shows a borderline negative decision, it might still be profitable to shove if folding means you lose all leverage.

When should I deviate from ICM-based shove ranges?

You should deviate when you have specific information about opponents’ tendencies or when future game considerations make a small -EV shove more appealing than waiting and risking an even worse spot. Factors like the blind schedule, your position next hand, and your opponents’ playing styles all matter.

Is pure GTO relevant when I am super short-stacked?

A GTO framework can provide a baseline for push-fold decisions, but real-world dynamics often require exploitative tweaks. Overly rigid adherence to GTO may ignore the advantage you gain by exploiting opponents’ mistakes.

Should I track my stack in terms of big blinds or M in these spots?

Both can be useful. Big blinds offer a quick reference for deciding push-or-fold ranges, while M takes antes into account. The right choice depends on your personal preference and the tournament structure, but either approach should be coupled with an understanding of your opponents and the blind schedule.

How can future game simulations improve my short-stack strategy?

Future game simulations can predict how upcoming hands will affect your stack if you fold too often or push at the wrong time. This broader context helps you weigh the costs of waiting versus the benefits of trying to preserve fold equity right now.

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