Guides / Effective Stacks
What Is an Effective Stack? A Guide to Stack Depth
Published Updated How these ranges are solved
Imagine this scenario, you have 200 big blinds, your opponent has 10. How deep is this pot really being played? Which stack defines strategy?
In this example, the smallest stack sets the ceiling for the pot size, and defines both players strategy. As a result - this is the effective stack.
The definition
The effective stack is how many chips are actually in play, given the stacks of the players in the hand. Heads-up, with just two players left in the pot, that is simply the smaller of the two stacks.
Multiway pots get a little bit more complicated, because the effective stack depends on the perspective you take. One definition is that you could consider the effective stack to be the second largest stack in play (since they define the most chips that could go into the pot from any one play). However, it's more useful to consider effective stacks from the perspective of each player.
An example
Three players are in a pot with 13bb, 9bb and 22bb.
- Player A - 13bb stack13bb effective
Covered by C, so A can only ever play for what A has.
- Player B - 9bb stack9bb effective
The shortest stack in the hand - nobody can win more than 9bb from B.
- Player C - 22bb stack13bb effective
Covers everyone, so C's ceiling against any one opponent is the next-largest stack (A's 13bb).
A and B are not covering anyone, so their effective stacks are capped at their own chips. C covers the table, so the most C can win from any one opponent is the second-largest stack - A's 13bb.
Why it matters
The effective stack determines the maximum size of the pot, and through that it determines which strategies are even available. Under roughly 10bb we are generally shoving or folding preflop; above that there is room to open to a non all in size.
Lets say that you are on the button with 40bb and it folds to you, but the small blind and big blind both have 8bb. Do you open to 2.2bb because your stack is 40bb? No. The effective stack behind you is 8bb, and against an 8bb stack we use a pure shove or fold strategy.
This mistake can get expensive: opening to 2.2bb with 40bb behind into a table of 12bb stacks means either folding to a jam over and over, or calling off with hands you never intended to play for stacks. You lose out on many of the benefits of a short stacked push fold strategy (such as equity realization).
The range you should be using
42% shove
Button, 8bb effective - your 40bb is irrelevant
ICM: effective stack is not the same as being that stack
In chip-EV you can more or less treat the button spot above as if your own stack were 8bb. The strategy comes out almost identical, which is exactly why push/fold charts are indexed by effective stack depth rather than by your literal chip count.
Under ICM that doesn't hold true. An 8bb effective stack does not mean you should play the hand as though you were the 8bb stack. As the covering stack you cannot be eliminated by this hand, so you carry none of the risk premium the short stacks are carrying - and they, on the bubble, would much rather fold and ladder than call off their tournament life. That asymmetry provides you with more fold equity, and it means that being a covering stack can jam wider - even if the effective stack is the same in both scenarios.
See what that looks like on a real bubble: five solved ICM shoving ranges.
Effective stack and hand selection
Stack depth changes which hands are worth playing, not just how much you can win with them. The logic is really about how a hand makes its money.
- Short effective stacks favour high cards. At short stacks, what becomes important is raw hand equity, and maximising fold equity through blockers. Playability is not important, because we only play a single street - and realize all our equity. As a result the shorter we get, the more offsuit high cards come into play.
- Speculative hands still have their place. Small pairs and suited connectors do not become unplayable at 12bb - they are perfectly good, sometimes excellent, shoving hands, because they hold real equity against a calling range and pick up fold equity on top. The benefit of realizing all of those hands equity has real value, because those times you don't hit a strong hand in deeper pots, you often end up having to fold out the equity you have against much pressure.
- Deep effective stacks benefit implied odds. Having deeper stacks behind with a lot of playability improves the value proposition of set mining and suited-connector type hands. The times you do hit a big hand, while infrequent now have a large enough potential payoff to be worth it.
Common mistakes
- Reading your own stack instead of the effective one. When you are the covering player, the number on your own seat is the least relevant stack in the hand. Multiway, the number that matters is per-opponent, and it changes as players fold.
- Forgetting the side pot. When a short stack is all in and two deeper players keep betting, the main pot is capped at the short stack's chips and everything after that is a side pot played at a completely different depth. A hand that started as a 9bb decision can be a 35bb one by the turn.
- Bringing deep-stack habits to a short table. Min-raising, floating and thin value-betting all assume streets that a 10bb effective stack does not have.
- Not taking into account ICM. Playing your 40bb stack like an 8bb stack near the bubble because the effective stack is 8bb, and giving up all the pressure that being the covering stack is worth.
Quick reference
The effective stack is the smaller of the stacks in the hand - the most that can actually change hands. Read it per opponent, in big blinds, before you act.
| Effective stack | Where the band sits, in big blinds | Band | What changes |
|---|---|---|---|
| Under 5bb | Desperate | Shove or fold, and position barely moves the range. A huge portion of your range becomes profitable to jam. | |
| 5-15bb | Push/fold | The shove-or-fold question is your primary decision. This is the band every chart on this site is built for. | |
| 15-25bb | Re-jam | Open-raising returns, but the main weapon against a raise is the 3-bet shove rather than seeing a flop. | |
| 25-40bb | Transitional | Raise-folding is affordable again and flops start to matter, but stack-to-pot ratios stay low. | |
| 40bb+ | Deep | Postflop strategy dominates hands. |
Reading the number is the easy half. Acting on it under time pressure is the half that costs money - so drill it: real spots, one decision each, scored against the solve.
Common questions
- What is an effective stack in poker?
- The effective stack is the most that can actually change hands between two players - in practice, the smaller of their two stacks. If you have 200bb and your opponent has 10bb, the effective stack is 10bb, because that is all either of you can win or lose. Your extra 190bb simply is not in play against that opponent.
- How do you work out the effective stack in a multiway pot?
- Take it one opponent at a time, from your own seat: against each player, the effective stack is the smaller of your stack and theirs. That means the number is different depending on whose seat you are sitting in. The biggest stack in the hand is effectively playing the second-largest stack, and everyone else is playing their own.
- If the effective stack is 8bb, should I just play like an 8bb stack?
- For chip-EV, more or less yes - your strategy against that opponent is close to identical whether you hold 8bb or 40bb. Under ICM it is not. A covering stack risks no elimination and applies real pressure to a short stack that would rather fold and ladder, so a 40bb stack shoving into 8bb blinds can jam meaningfully wider than an 8bb stack in the same seat would.