With so much postflop play, it might seem like cash games are more difficult than tournaments.
The best tournament players, however, are adept at playing every street across a range of different stack depths.
In this article, we’re going to learn about stack-to-pot ratio (SPR) and how it affects postflop play. We’ll be looking at three examples with different SPRs:
Let’s get started!
What is Stack-to-Pot Ratio?
Stack-to-pot ratio (SPR) is exactly what it sounds like: the ratio of the shortest stack in the hand divided by the pot. SPR is calculated on a street-by-street basis.
For example, suppose you’re playing a $2/$5 cash game in which every player has a $500 stack. You raise from the button to $15 and only the player in the big blind calls.
The pot is now $32 (we’re playing in a magical world with no rake) with $485 stacks behind. So, the SPR in this case is:
As the SPR increases so does the complexity of the game and thus the role of skill. 15.15 SPR is quite high, so there will be a lot of postflop maneuvering in this hypothetical hand.
To help you better understand SPR and its importance, here’s a snippet from the Upswing Lab:
SPR is useful for determining postflop hand strength.
With a SPR of 1, [AT] on [T87] is very strong and can be played for all the remaining chips. By contrast, if the SPR was 10, [AT] it would be medium strength at best, and would be a disaster to get all-in.
Here’s a good rule of thumb for SPR: small SPR spots are where one pair/top pair hands reign supreme, whereas bigger SPR situations call for two pair or better to play a large pot, and expect to win.
Now, let’s dive into the hand histories.
Deep: 10+ Stack-to-Pot Ratio
Deep SPR hands are a strong poker player’s bread and butter. These are single raised pots in cash games and in the early stages of tournaments, where most players will be sitting with 70 big blinds or more.
Many poker players consider themselves experts in these spots, but these players often time fail to consider what the SPR will be on later streets.
The following hand example is one many of you might be familiar with, played between James Obst and Michael Ruane with 25 players left in the 2016 WSOP Main Event.
It was one of the most memorable hands of the tournament due to a staggering river fold from Obst. Our analysis, however, will focus on how SPR affects play on each street rather than Obst’s famous river fold.
The blinds are 100k/200k. Fernando Pons opens UTG to 450k with K♦ Q♦. Ruane then calls on the button with 9♣ 8♣, Obst calls in the small blind with 7♥ 7♦, and Nguyen calls in the big blind with 9♥ 6♣. The four players take a flop of:
Talk about an action flop! Obst has flopped bottom set, Ruane a gutshot straight flush draw, and Pons, the preflop raiser, top pair with a good kicker.
With a pot of 2.025 million, the stack sizes and SPRs are as follows:
- Pons’ 17.7 million chips — 8.74 SPR
- Ruane’s 21.5 million chips — 10.62 SPR
- Obst’s 25.4 million chips — 12.54 SPR
- Nguyen’s 5.8 million chips — 2.86 SPR
Pons continues for 625k. Ruane raises to 2.025m, and Obst comes over the top with a cold 3-bet of 5.3m. Nguyen and Pons promptly get out of the way, leaving the action on Ruane.
This is an easy call for Ruane. His hand doesn’t play well as a raise against Obst’s flop 3-betting range, which will contain at best top two pair, and at worst bottom set or a stronger flush draw.
More interesting is Ruane’s initial raise. Though a perfectly fine play, it’s important to consider the SPR implications for the turn if he were to face a 3-bet, which is of course what ended up happening.
Not only can Obst have all of the aforementioned hands, Pons can feasibly have all of the sets (especially in a 4-way pot with this board texture, where he’s less inclined to check top set), as well as stronger flush draws.
If either Obst or Pons decides to 3-bet, Ruane will have to call, and this will leave an SPR of just over 1 going to the turn. This means that if his opponent decides to jam on a brick turn, Ruane will have to fold and give up substantial equity.
Folding a high equity draw because you don’t quite have the required odds to call a jam is a situation we should try to avoid. In this case, by flatting instead of raising on the flop Ruane could have comfortably played every turn and river. This is especially the case with a combo draw like 9♣ 8♣, because he’ll have enough equity on the turn to comfortably call a large bet.
Ruane calls the 3-bet, and the turn is dealt:
Ruane hits his straight flush, leaving Obst drawing dead. The pot is now 13.265m. Ruane is sitting with 16.2m behind, and Obst covers him with 20.1m behind, giving an SPR of 1.19.
This is when the hand starts to get wacky because of the massive money at stake.
Obst checks to Ruane, who bets 3.75m, or about 28% of the pot.
Obst’s check makes sense. He is firmly behind Ruane’s range now that the flush has come in, so betting is out of the question.
Ruane’s decision to bet such a small amount, on the other hand, has its pros and cons. On the one hand, it gets value from top two or a set, which his opponent very likely has, and it leaves a sensible SPR on the river. On the other hand, it hampers Obst’s ability to call and draw to a boat with QJ, and makes it less likely that he’ll bluff on the river when he has a hand like KT or T9.
Obst calls, getting almost direct odds to boat up, and the river is dealt:
Things just keep on getting worse for Obst! He now has a full house, with an SPR of 0.6, which means Ruane should always be doubling up here. (And if it were any other tournament, he certainly would.)
Obst makes an oddly small river bet of 4.7m, but it’s easy to see why: he’s trying to get guaranteed value from flushes while also trying to avoid being crippled if he’s beat. However, when the SPR is this low, the only bet size that makes sense is all-in—anything less results in missed value and an awkward spot to balance.
Ruane raises Obst all-in to 12.48m. Obst, getting almost 5 to 1 on a call, makes a tournament-saving fold.
One could argue Obst’s play is reasonable given the situation–nearing the final table of the Main Event. But theoretically, it’s a clear misstep.
The takeaway, here, is that as the SPR gets deeper, we have to be stricter about which hands to get it all-in with.
Medium: ~5 Stack-to-Pot Ratio
Medium SPR hands are typically either 3-bet pots played around 100 big blinds deep, or in single-raised pots played around 30 big blinds deep, such as those played in the later stages of tournaments.
For this section, we’ll look at a hand played by Doug Polk fairly early in the 2016 $2,100 PokerStars SCOOP.
The blinds are 150/300 and Doug is the effective stack in this hand, sitting with 11.8k.
The Villain in the hand opens to 750 in the hijack, the player on the button calls, and Doug calls in the big blind with K♥ 7♥. The flop is dealt:
Villain continues for 1.2k and the button folds.
This is an interesting spot for Doug. With an SPR of just over 4, both raising and calling with his flush draw seem like viable options.
If the SPR was a little lower—if he was sitting with, say, 8k—then check-raising all-in becomes much more preferable. This is because we’ll win more relative to our stack size for an all-in bet.
Likewise, if the SPR was a little larger—with a 15k stack, for example—then calling becomes more desirable. A check-raise all-in would be an unnecessarily large overbet, and check-raising to a smaller size puts us in an annoying spot if we get jammed on.
Doug makes the call, and the turn is dealt:
The pot is now 5.2k and Doug is sitting with 10.2k behind, making the SPR almost exactly 2. Doug checks, Villain checks back, and the river is dealt:
Now, Doug has a decision to make: does he go straight for river value with a bet, or go for the river check-raise?
In this situation with such a strong hand, check-raising makes the most sense for two reasons:
- Check-raising will win a larger pot on average than a bet, which we obviously want with such a strong hand.
- Check-raising with strong hands also allows us to check-raise with bluffs, which makes our entire range profit more.
Addiotinally, Villain can conceivably have many hands that will bet, and some of those will call a check-raise. We can balance our range by check-raise bluffing with hands that contain a single high heart, such as A♥ 2x.
Doug goes for the check, and Villain bets 2.4k. Doug check-raises all-in–the size we should always choose with an SPR of around 2–and Villain calls with TT.
Short: <2.5 Stack-to-Pot Ratio
Hands that see a flop with an SPR of below 2.5 are typically in either 4-bet pots played with regular cash game stack sizes (e.g., around 100 big blinds), 3-bet pots in the later stages of tournaments, or in single-raised pots in which the big blind defended with less than 15 big blinds.
We’re going to look at the latter situation. It’s a fairly common and somewhat awkward spot that is often misplayed.
Editor’s note: If you rarely defend your big blind with less than 15 big blinds, I highly recommend reading our guide on How to Combat Steals with a Tiny Stack.
Let’s consider a hypothetical example this time. The blinds are 500/1k with a 100 ante. Our hero, James, is in the big blind with 13k. Our villain, Sean, is on the button with 68k.
The action folds to Sean, who opens to 2.1k. The small blind folds, and James defends with T♥ 9♣. The flop comes:
The pot is 5.6k, and James has 10.6k behind, making the SPR just under 2. Sean c-bets for 3.3k.
In this situation, we can check-raise all-in because the SPR is so low. With a deeper SPR, check-raising with a medium-strength top pair is a bad move because we’ll often get called by better hands, and put ourselves in awkward turn spots with a needlessly inflated pot.
With an SPR this low, we can check-shove to deny equity to our opponent, whose c-bet range will contain lots of over-card combos that have a decent amount of equity when called. This puts our opponent in a frustrating spot, as the decision between calling or folding will often be very marginal. We can also get value from hands like 88, 99, weaker Tx hands, and draws.
Now, because we very often have a value hand when we check-shove all-in, we’ll need to include lots of bluffs for balance. On this board, there are plenty of flush and straight draws we can use, such as 98s, 65s, or a flush draw.
The important thing to remember here is that as the SPR gets lower, the range of hands we need to be willing to “go with” gets wider. When we flop a pair with an SPR below 2.5, often we’ll either have to check-raise all-in to protect our equity or just call down.
Stack-to-Pot Ratio Wrap-Up
I hope you’ve found this article on SPR helpful. Here are the two main takeaways:
- Always consider the strength of your hand relative to the SPR on the flop. For example, if you have top pair top kicker with an SPR of 10+, getting it all-in is super bad, but the same hand with an SPR of 3 is effectively the nuts.
- If you have a draw try to avoid situations where your opponent can jam and force you to give up your equity. Instead, look to play the hand in a way that lets you jam yourself so you force your opponent to fold their equity.
Until next time!
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