Definition of SPR. Now that we know what 'effective stack' means, the stack-to-pot ratio is defined as follows: SPR = Effective stack / Pot. If all players have $500 stacks and there's $20 in the pot, your SPR is 25. This is a very high SPR. You could be looking at a huge pot and you need to plan your game accordingly. The REM process was first introduced by Flynn, Mehta and Miller in the book Professional No-Limit Hold'em: Volume I (the same book that introduces SPR). This article will be split up in to 3 sections, covering the basics of the REM process to make it as easy as possible for you to pick it up and incorporate it in to your game.
This article was written by blackrain79.com contributor Ryan Lewis.There are all sorts of mathematical equations that can be utilised in poker to assist players to help with their decision making in game.
In order to become successful long term players, we must have a good understanding of poker math theory so it can be applied in real time during live or online play.
Although not the most sexiest subject in the game, a lack of understanding in basic math can lead to costly errors down the track and force our win rate or return on investment to take a substantial hit.
In this article I will introduce the stack to pot ratio equation and how you can use it in game to boost your win rate and results.
What is the stack to pot ratio?
The stack to pot ratio (SPR) is a simple basic calculation that tells us how much we are willing to risk to win a hand.
The equation is calculated post flop and applies on the flop only and before any betting is done. The formula is:
For example, we head to the flop as the pre flop raiser and only the big blind calls. The pot size is 6.5BB. I have 97BB in my stack, the big blind has 40BB in theirs.
The effective stack is 40BB, as I can only win what the big blind has remaining. The stack to pot ratio is: 6.2
6.2 = 40 / 6.5
Depending on what blog you read or what poker book you have, you will find that there is conflicting information on what a low, medium and high SPR is. Some books will say that a low SPR is 2.5, others will say 3-4, and then others will say 6.
As per usual in life the answer lies somewhere in the middle.
Through experience of playing hundreds of thousands of hands I have come up with my own conclusions on optimal stack to pot ratio numbers:
- Low SPR: < 4
- Middle SPR: 4-10
- High SPR: > 10
How to interpret the stack to pot ratio
By calculating the SPR we can make a logical decision if we want to play for all the money on the flop.
Below is a hand strength guide which we can use to determine how willing we are to play for all the money on the flop based on the stack to pot ratio:
The basic premise is the higher our SPR is, the higher our hand strength must be to auto stack off on the flop. Overpairs also do well in SPR’s of 6 and below.
Bare also in mind that these numbers are fluid. If you have a specific read on villain and know they like to stack off light, then getting it in with top pair when the SPR is 6 is viable.
Another point to keep in mind is 3bet pots usually create an SPR of roughly 4. This allows you to stack off comfortably with top pair and overpair type holdings.
Draws can be tricky to play with middling SPRs because you can be forced to call it off on the flop if you are presented with the right pot odds.
This can happen if you check raise the flop from the big blind with the nut flush draw and then face a jam. If presented with correct pot odds I advise to make the call, even if the SPR suggests otherwise.
Examples of using the stack to pot ratio
Alright, let's look at a few different examples of using stack to pot ratio in poker. Hopefully this will give you a better understanding of how to use SPR at the tables yourself.
Low SPR example
Button (Hero) 100BB vs BB (villain) 26BB
We hold A♠ K♣
Flop
4♠ 8♦ A♥
Pot is 6.5BB, SPR is 4. Villain donks for 3BB.
Hero should raise to 9BB and look to call a jam from the BB.
This is an easy stack off opportunity on the flop. We flop top pair top kicker in a low SPR of 4.
Middle SPR example
Button (Hero) 100BB vs BB (villain) 50BB
We hold 4♥ 4♣
Flop
4♠ 6♦ 7♦
Pot is 6.5BB, SPR is 7.7. Hero cbets 4BB. Villain check raises to 12BB.
Hero should jam.
Here the SPR is a little higher at 7.7. We flop bottom set and face a check raise on a wet board.
On this flop we should look to get it in immediately as there are many cards on the turn and river that will kill the action.
Any diamond, 3, 5, 8, 9 and T (almost half the deck!) are bad cards for us and we would rather get our money in on the flop when we are ahead the majority of the time.
High SPR example
Button (Hero) 100BB vs BB (villain) 100BB
We hold A♠ A♥
Flop
8♠ 8♥ 5♥
Pot is 6.5BB, SPR is 15.4. Hero cbets 2.5BB. Villain check raises to 10BB.
Hero should call.
In this example the SPR is high at 15.3. Our threshold for stacking off on the flop at this level should not be overpairs. Hero should call and reassess the action on the turn.
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How the stack to pot ratio can help your poker win rate
Here are a few concepts we can use both pre flop and post flop to assist us in how we plan a hand. First we need to take note of our opponents' stack sizes.
One of the most important and underrated skills we can undertake is to be more aware of our opponents stack size when heading to the flop.
Once we have a rough idea of the SPR, we can plan accordingly and decide whether we want to play for all the money before we perform our action.
You should have a rough idea of the SPR in every hand you play.
We can also exploitatively fold and not cold call marginal holdings such as low pocket pairs and suited connectors pre flop when facing an open raise from a short stacked player (60BB or less).
These holdings perform best with SPRs of 10 and higher.
The logic here is that you need to have the opportunity to win a large pot to balance out all the times when you call a raise and are forced to fold when you miss.
This is something that Phil Ivey talks about in a lot more detail in his recent MasterClass poker training.
Tailor your preflop bet sizing to your preferred stack to pot ratio
This situation will occur usually when we face opponents who open limp with a short stack. The general advice is to isolate the limper by raising to 4BB if you have a hand worth playing.
I would add to this advice that you can and should exploitatively raise larger to at least 6BB (or sometimes higher) when you hold a high pocket pair.
The limper will still call the majority of the time and by raising larger you create a larger pot heading to the flop which creates a smaller stack to pot ratio.
Smaller SPRs benefit big overpairs as you can easily get it in on the flop if facing aggression. By the way, I have already written the complete guide on when to fold your overpair.
We can also use this advice when 3 betting. Instead of 3 betting to a conventional 9 or 10BB we can opt for a larger sizing, such as 11 or 12BB.
If our 3bet is called we often head to the flop with an SPR of under 4 (assuming we are playing for 100BB), which can make our decisions easier if we decide to play for all the money.
I would advise against opening the pot (meaning we raise first in before any limpers) pre flop to a sizing higher than 3BB.
Even though this creates a smaller SPR, it forces your opponents to play perfectly against you by calling tighter and 3betting hands that have you crushed.
Unless there are major whales at your table, your raise first in size should be between 2.5-3BB. Remember we make money in poker from our opponents mistakes, not by forcing them to play well.
Proceed with caution when playing deep stacked
There is no worse feeling in poker than accumulating a 200BB stack, only to lose it all after overvaluing an overpair or the low end straight. Or having to think about folding bottom set on the flop when the SPR is 30.
Personally I hate playing deep stacked and to this day I avoid it like the plague. I make a conscious effort to reload the table once my stack is 150BB or higher.
I prefer to keep my decisions as simple as possible at the table and I achieve this by sticking to a stack size of around 100-150BB.
Poker Spring
I'm not saying that you should do this as well but mastering how to play one stack size is superior than being average at short, regular or deep stacked.If you stick to one stack size then you get used to what the SPR’s will be and your post flop decisions will become much easier.
If you find yourself playing deep stacked for 200BB often then be aware that the SPR will be between 25 and 30 routinely.
That means your threshold for stacking off on the flop should in theory be much higher and will be narrowed down to middle and top set, and nutted flushes and straights.
For much more on playing optimal deep stacked poker (and how to use SPR when super deep), check out the The Upswing Poker Lab.
Final thoughts
The stack to pot ratio is a simple math calculation we can utilise on the flop to decide how willing we are to risk our stack to win the hand.
The higher the SPR is on the flop, the higher our threshold and hand strength will be for getting all the money in.
Try and make a habit to know what the SPR is every hand you play so you know how to proceed on the flop if you face aggression.
In doing so it will allow more clarity in our post flop decision making process.
Lastly, if you want to know the complete strategy that I have used to crush small stakes poker games as a 10+ year pro, make sure you grab a copy of my free poker cheat sheet.
Poker Spring
This article was written by Ryan Lewis. Ryan specializes in 6max cash small stakes online poker. He focuses on playing a fundamentally strong tight and aggressive strategy. He particularly enjoys the statistics and game theory side of the game. You can follow him on Twitter right here.
Let me know your thoughts in the comments below on stack to pot ratio. Do you use stack to pot ratio at the poker tables to improve your decision making?
SPR, short for stack-to-pot-ratio, is a powerful concept that can help you take better lines both preflop and postflop. If you can understand and apply SPR strategy in poker you will have a mathematical framework for commitment. Here is the SPR formula: SPR = Effective Stack Size / Pot Size.
Stack to Pot Ratio, or SPR for short, is a tool for helping to plan your hand around commitment decisions. In short, by providing a quick, easy framework for relating the size of the pot to the remaining effective stacks, you’ll be able to more easily determine if your hand strength warrants playing an all in pot or not.
Let's get a firm hold on using the stack-to-pot ratio (SPR) to take the best action in your next tournament. Profitable poker is a matter of defining the best risk for the potential reward for. Stack To Pot Ratio. In Professional No Limit Holdem, the authors describe how our decisions vary based on the size of the pot in relation to our stack. For instance, if we had pocket kings on an Ace hi flop with a pot of $1, we might play the hand differently if we had 1 cent behind, than if we had $100 behind. SPR What Does It Mean in Poker? SPR stands for Stack-to-Pot Ratio, which is the ratio of the shortest stack in the hand (aka the effective stack) divided by the pot on any given street. For example, if the pot is $10 and the effective stack is $100, the SPR is 10 (100/10).
Calculating SPR
SPR is easy to calculate. It’s the ratio of the size of the pot, to the size of the effective stack (chips still left to bet). So if there is $50 in the pot, and $100 left to bet, the stack to pot ratio is 2 (100/50). The important thing to remember is that SPR is calculated by the effective stack. If we had $2000 in the example, but our opponent only had $100, then the SPR with them is 2 since $100 is the most we can bet before they are all in. It is also possible to have different SPR’s with different opponents in multiway pots. If there was a 3rd player in the above hand, who, like ourselves, also had $2000 left to bet, then the SPR with the short stack player is still 2, but our SPR with the third player is 40 (2000/50). We would be willing and profitable to play many hand strengths all in vs. the short stack that would not be profitable to play all in vs. the other big stack.
Example:
As a basic example of extremes to help illustrate, suppose you have AhAd and the flop comes KsTc3d. Are you willing to get all in on the flop? If the pot contained $10 and the effective stacks had $1000 behind to bet (SPR of 100), getting all the money in would be rather insane and a losing play, because no one in their right mind will put 1K more in the middle in a $10 pot with a hand that can’t beat 1 pair. If, however, the pot contained $1000 and you had $10 left to bet (it’s an exaggerated hypothetical, bear with me here), of course you’d put that last $10 in. You would even put the last $10 in without a connection to the board… not only because you have a correct price to draw to anything, but you may have the best hand right now with something like ace high or king high as your opponent will eagerly (and correctly) put the last $10 in with any 2 cards and 1K already in the pot.
Practical Application
The lower the stack to pot ratio, the larger the pot is relative to what’s left to bet. Thus, opponents will be getting a better price to play for the rest and should be willing to do so with lessor holdings. While the example above was made with extremes, it should be clear that this is the basic logic of SPR.
One of the ways we can use this tool is to understand what kind of SPR we might have on the flop that will allow a player to get all in on the river with reasonable sizings. For example, if the stack to pot ratio on the flop is 13, it will take exactly 3 pot sized bets to be all in on the river. We can see this if we walk through the betting each street as follows:
Pot size = P
Effective Stack = 13P (SPR = 13)
If we bet 1P on the flop and are called, there will be 3P total going to the turn, and we’ll have 12P left to bet. On the turn we pot it again betting 3P and are called again. Now there is 9P in the pot, and 9P left to bet for a pot sized river all in.
You can work through a similar process for various effective stack sizes, and bet sizes. Let’s conclude with some general (not written in stone) guidelines for certain flop SPRs and willingness to play for all the marbles:
Poker Sprint Planning
SPR 4 or less: This low SPR on the flop is one where we should feel comfortable getting our stack in with strong 1 pair hands. It will only take 2 pot sized bets to get all in, or 3 smaller sizings, and most players will have a hard time folding their pairs, particularly their better ones, in this sequence.
SPR 10 or more: The higher SPR’s make it precarious to get stacks with one pair hands. The more money there is to bet relative to the pot, the less likely an opponent will be to put it all in the middle without a very strong hand.
SPR 4 to 10: These middle of the road stack to pot ratios on the flop can go either way. Take the AhAd and the flop comes KsTc3d example from above. If our opponent were a known calling station, we can feel very comfortable getting in across 3 streets even on an SPR of 10, because stations will pay us off with many worse one pair hands. If our opponent were a very tight, conservative player however, we may not be retaining much edge getting all the money in on an spr of 5, because that opponent type is loath to play for stacks without very strong hands. What if you have no reads? In micro stakes, it’s safe to err on the side of assuming players will call too loose and too often, and be willing to go for the value with your strong one pair hands at a bit higher spr’s.
The basic premise of stack to pot ratios is simple… the larger the stacks relative to the pot, the stronger a hand we need to be willing to stack it all off. And when the money left to bet is shallow relative to the size of the pot, we should be reluctant to give up on that (relatively) large pot and willing to get in much lighter.
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Do you take SPR into consideration?
Note – SPRstands for Stack to Pot Ratio.
Poker Term Splash The Pot
I think a lot of SPR importance is based solely on the texture of the games you are playing in. To say a general statement like 'SPR of 13 is bad for top pair' would be wrong, since with aggressive history 13 is an amazing, optimal even, spr for top pair.
Poker Term Spring
I don’t even really see how you could discuss spr as a theory, its just something you should intrinsically keep in mind.
One thing related to spr that I’ve always found fascinating, but difficult to describe:
Poker Strategy seems to involve lots of dualities, wax/wane dynamics. Few examples of these:
Poker Term Spr
– You have a gutshot and an overcard first to act on the flop in a heads up pot, with x dollars in the pot, and effective stacks F(x). If F(x)=x its an easy shove. If F(x)=2x its an easy c/f, if F(x)=4x bet folding or c/rai can be correct. If F(x)=8x then you might bet 3-bet. Its basically a sine wave that decays as x approaches infinity.
– Unbalanced range leveling. Basically whether you decide to bluff someone when its obvious their range is mostly bluffcatchers vs yours. You’ll not bluff if you expect a call given your history, assuming your on that level, or you will decide to use that information as an excuse to bluff even. Your opponent will have to decide what your level F(x) will be. If he feels you’re a str8forward player he’ll set F(x)=1 and fold, but as he sets F(x) to higher and higher numbers his analysis will become basically useless and he’ll simply assume you are bluffing a decent amount and end his analysis right there. Once again, decaying curve.
Poker Sprinkles For Cakes
Anyways I guess when ppl are in quote/unquote 'tough spots' that just means that they are not at one of the relative peaks/troughs of the sine wave, and are instead toward the equilibrium point.
This is why 4-bet bluffs are so tough to deal with with 75 and 150bb stacks, and so much easier by comparison to deal with when stacks are 100bb or 200bb deep.