The meaning of stack to pot ratios or SPR in poker is a common question among players learning the game. While it seems like a complicated concept at face value, its meaning is actually based soundly on common sense. I have been writing about and teaching how to use SPR for almost a decade and will tell you all you need to know to use it to improve your game.
What does SPR mean in poker? Stack-to-pot ratio, or SPR, is a mathematical solution to figuring out a poker player’s commitment level on any given flop in cash games. The SPR is represented numerically and is calculated by dividing the amount of the flop into the effective stack size of the players involved in the hand.
SPR is usually associated with being a cash game concept. This is because commitment works quite a bit differently in tournaments since the speed of the event and the nature of the prize pool can drastically affect your level of commitment at any given time. However, learning how to use SPR as a tool will broaden your understanding and will certainly help you make better decisions in any format.
What Is Stack to Pot Ratio (SPR)?
The concept of SPR was first introduced in the book “Professional No-Limit Hold’em“, often known as PNLH, back in 2007. It basically turned something that is common sense into a method of using simple math to systematize how to determine your commitment level on the flop.
What is Commitment?
This is another useful gem discussed in PNLH. Commitment basically means that once you invest a certain percentage of your stack in the flop, it is often less profitable to fold than it is to go ahead and continue and fight for the pot. The authors indicate that once you put 33% of your stack into the pot, you are committed to it.
In other words, if the flop comes down and you flop a particular hand SPR tells you whether you can bet big on the flop and commit 33% or more of your stack immediately and profit from the action long term.
How Does SPR Work?
In a nutshell, SPR roughly tells you how strong your hand needs to be to profitably get all-in on the flop. This allows you to more accurately play your hands and avoid overcommitting (or undercommiting). To figure out the SPR all you have to do is divide the pot size on the flop into the effective stack.
For example, you have 40 big blinds before the flop and open raise to 3 big blinds. You are called by both blinds. The pot going to the flop is 9 big blinds and the effective stack is now 37 big blinds since your 3 big blind open raise is already committed to the pot. 37 divided by 9 is 4.1, which is the SPR.
Basically, once you know your SPR all you need to do is figure out if you hold a hand that can commit, or whether you need to bet and fold to a raise or avoid getting raised at all by checking back and allowing you to get to later streets and keep the pot small (since you aren’t committed).
Why is SPR Useful?
Knowing a “target” SPR for a particular type of hand allows you to create situations on the flop that are favorable to the type of hand you hold. For example, if you hold a hand that often makes a strong top pair hand (like AQ) you can tailor your opening raise or reraise so that you achieve your target SPR in order to be able to profitably commit on the flop.
I have spent years using and expanding on how to use SPRs in a practical sense while writing my books and creating videos and courses for my students. While the book gives a somewhat rudimentary (and groundbreaking) way to figure out how to play hands after the flop, I have further codified exactly what types of hands you can commit with on various flops.
However, it’s impossible to cover every single way that SPR can be affected by a table dynamic. Such an endeavor would be worthy of an entire book and I can’t hope to do it full justice here in one article. Even so, I will give you a fairly detailed example of what types of hands can be committed against 3 different opponent types.
Before you look at the chart I have provided below, let me clarify something. The example below is based on a fairly generic flop texture. Keep in mind that, as a rule of thumb, you can stack off a bit wider on wet boards and you need to stack off a bit tighter on dry boards. This is because the wetter the board, the more hand combos an opponent will have. Thus his stack off range will naturally be wider. In other words, the board will “force” him to become a looser opponent.
With that stipulation out of the way, here are the hand types that can typically be committed with on the flop based on the stack-to-pot ratio.
Target SPRs Versus Different Opponent Types
|SPR||Normal Opponent||Loose Opponent||Tight Opponent|
|.25||Any Pair, 3+ Outs||Any Pair, 3+ Outs||Any Pair, 3+ Outs|
|.5||Any Pair, 6+ Outs||Any Pair, 6+ Outs||3rd Pair, 7+ Outs|
|1||2nd Pair, 8+ Outs||3rd Pair, 7+ Outs||TPWK, 8+ Outs|
|2||TPGK, 9+ Outs||2nd Pair, 8+ Outs||TPGK, 9+ Outs|
|3||TPGK, 10+ Outs||TPWK, 9+ Outs||TPTK, 12+ Outs|
|4||TPTK, 12+ Outs||TPGK, 10+ Outs||Overpairs, 13+ Outs|
|5||TPTK, 13+ Outs||TPGK, 10+ Outs||Overpairs, 14+ Outs|
|6||Overpairs, 13+ Outs||TPTK, 11+ Outs||Two-Pair+, 14+ Outs|
|7||Overpairs, 14+ Outs||TPTK, 12+ Outs||Two-Pair+, 14+ Outs|
|8||Two-Pair+, 14+ Outs||TPTK, 12+ Outs||Sets+, 15+ Outs|
|9||Two-Pair+, 14+ Outs||Overpairs, 13+ Outs||Sets+, 15+ Outs|
|10||Sets+, 15+ Outs||Overpairs, 14+ Outs||Sets+, 15+ Outs|
*TPTK, TPGK, TPWK= Means top pair “Top”, “Good”, “Weak” kick respectively.
By the way, determining profitable stackoff ranges is all about the math. The equity that you need to get all-in versus different ranges is all determined by the SPR. Here is a graphic showing the equity needed at each SPR.
You’ll note that once you get to about a 5 SPR, the amount of equity needed doesn’t really go up that much anymore. This might lead someone to falsely believe that your range for stacking off doesn’t change that much beyond a 5 SPR.
The only problem is that as the SPR grows, people will naturally tighten up the hands they are willing to stack off with. So when considering a stack of range at say 10 SPR, you have to have 47.6% equity versus the nut range or strongest hands your opponent can have. Of course, it does matter what opponent you are facing since not all poker players have the same thresholds for stacking off with various parts of their range.
Why Does the Opponent Type Matter?
The best way to explain this is to take a look at an example. Let’s say you have top pair good kicker on a typical neutral board texture. Basically, your equity versus different opponent stack off ranges is what determines your commitment level. Loose players stack off wider and tight players stack off tighter.
Here is the setup. We need to figure out our stack off range on a J♠8♥2♣ board. The SPR is 5 and we face two different possible opponents. A really tight one and a very loose one.
Tight Player Stack Off Range
Loose Player Stack Off Range
Let’s see how top pair top kicker does versus these ranges to give us a baseline for what SPR we need to stack off.
TPTK Versus the Tight Player
TPTK Versus the Loose Player
The results are rather striking based on the equity differences. We would need an SPR of much less than 5 to stack off versus the tight player while we can slam dunk get it in versus the loose guy.
Keep in mind that an opponent’s commitment range will change based on the SPR and you constantly have to reevaluate his range. To illustrate, based on the examples we just used above, if the SPR was 2 the tight players stack off range would likely look more like the loose players SPR 5 stack off range.
So What Hands Do We Need Versus the Tight Player?
We know we need 45.5% equity to stack off with an SPR. If you look at target SPR chart I showed you earlier, you will see that it says you need an overpair or a 13+ out draw. Since a 13 out draw isn’t possible on this board, we can only look at overpairs. Let’s take a look at an example and see if the chart is accurate:
Board= J♠8♥2♣ , Opponent= Tight
We fall just a bit short of our target percentage. However, since poker is a game of frequencies, if our opponent is stacking off with a QJ or T9 (perfectly reasonable) any amount of the time QQ becomes a no-brainer to commit here.
Besides, with fold equity, if we got raised on this flop there is always a small number of times that our opponent could be bluffing. Therefore we would never want to fold QQ here. Moral of the story, if you are going to fold an overpair to a raise on the flop, you probably should not be betting in the first place.
The Effect of Board Texture
As a rule, you can widen your SPR requirements on wet boards. That’s because there are more draws out there, which makes made hands go up in value when considering commitment.
I challenge you to set up the last example for yourself in Pokerstove or Equilab and change it to a two-tone board. Rerun the equities figuring in how you think each player type would commit with flush draws figured in. I’m sure the results will help clarify your understanding of how SPR and commitment works.
How to Use SPR
The first thing you should always do when the flop comes down is to check the SPR. This is what I teach my students and doing so can only help you play better post-flop poker. Even if you only have a basic understanding of how commitment works you will be worlds ahead of most of your opponents.
Here are a few general tips for using SPR:
- Adjust Your Opening Raise Size- Tend to open raise a bit bigger pre-flop with hands that make top pair. This will create easier decisions for you after the flop.
- Use the Rule of Two When First Learning- What I mean by this is, once you figure out your target SPR, adjust it by 2 one direction or the other if your opponent is overly loose or tight. So if you need an SPR of 5 to stack off in a normal table dynamic and are in the pot versus a tight player, you need a 3 SPR. If the opponent is loose, you need a 7 SPR. Your mileage may vary since some loose players will be slightly looser than normal and others will be downright maniacs. Be sure to adjust commensurate with the extreme tendencies of an opponent.
- Don’t Forget to Factor in Board Texture- You can further fudge your SPR by at least 1 based on the board texture. If your required SPR is 5 and the board is something like JT7, change it to 6. If the board is dry, something like A92, then change it to 4. Once again, your mileage may vary based on what degree the board is either wet or dry.
Using SPR in Tournaments or SNGs
Similarly to how you adjust SPRs based on the read you have on opponents, you could similarly rely on the speed of the tournament and which stage you are in to calculate your commitment level.
These are a few things to keep in mind:
- Playing Turbos- The faster the blinds go up, the looser your SPR requirements need to be. This is because you will be constantly under pressure to keep building your stack. Whereas in cash games you generally want to play conservative in marginal situations, in tournaments you usually want to push every small edge you have to the maximum.
- Playing Slow Tournaments- The slower the tournament, the more you can tend to play as if you are in a cash game. This is especially true when you are 40 big blinds deep or greater. Patience is a lot more correct in these situations.
- Playing the Bubbles- Most players tighten up around both the money and the final table bubble. Since stack off ranges will be tighter, you can loosen your equity and SPR requirements for stacking off. The more top-heavy the tournament is, the looser you need to be.
- Double or Nothing Tournaments- With a smooth payout structure where the money is spread out evenly, you need to play much tighter than you might think. While fold equity will be higher, there is still not much incentive to take marginal all-ins at any point in the event. The exception is when you are the shortest stack at the table. In that case, you have to be a maniac most of the time.
I hope this article has helped clarify your understanding of SPRs and that you are now better armed to tackle post-flop. One final tip: If you want to create better SPR scenarios for yourself, a great option is to try playing a short or mid stack. My favorite starting stack size is 30 big blinds due to the advantageous SPRs it affords me.
I have created a free short stacking strategy guide that includes charts that tell you exactly what to do. If you want to check them out, sign up for my newsletter below. Thanks for reading!