by Stack pot ratio, or SPR, is a way to calculate how deep the effective stack size of the players in the hand is and what sort of risk they’re taking for a shot at winning the money already in the pot. It can be a very useful metric to have at your fingertips. If you’re in a one SPR pot and make a strong hand, then you can plan on checking back the flop to see if your opponent continues to raise and then making an easy decision about whether to check-jam or call on later streets.
The important thing to remember about SPR is that it’s always changing. The SPR you start with on the flop will be different than it was preflop, for example, because of betting done during preflop that changes the value of each player’s stacks. Also, the revelation of each street and community card makes the pot bigger or smaller. This all changes the SPR for each player, and you can recalculate it at any time.
SPR is also affected by the number of opponents and their stack sizes. For example, if you’re playing in a live game with a straddle, this will cause the SPR to change dramatically. The same is true of splashed pots where the casino fronts X amount of money into the pot before any cards are dealt. The result is often a lower SPR, which can lead to a lot of action on the flop.
It’s also worth considering SPR for different types of hands. If you have a strong but vulnerable hand like AA on 875 spr, then it’s a good idea to play it a bit more carefully when there is high SPR, as it could be easily called by a weaker opponent. On the other hand, if your SPR is low (between 2-3), you might want to be more willing to just take it all in with this hand.
Another aspect of SPR that is often forgotten about is how it varies between fish and regs. In general, regs are more likely to be able to play an overpair on a low SPR, whereas a fish will probably prefer to call the preflop raise on a high SPR and just take their chances in the middle. This is one of the reasons that SPR is a much more valuable tool for understanding your opponent’s style than just looking at their stack size.
