SPR is the effective stack divided by the pot at the start of the flop. It tells you how committed you are: low SPR means top pair can stack off, high SPR rewards implied odds and pot control.
SPR sets how strong a hand you need to commit your stack. At a low SPR (under about 4), top pair or an overpair is often good enough to get all-in profitably, so play fast and straightforward. At a high SPR (10+), the same top pair prefers pot control, because stacks only go in when you’re usually beaten.
You influence SPR before the flop: 3-betting and 4-betting lowers it, while calling to keep the pot small keeps it high. Planning around SPR is how you avoid the classic trap of bloating a pot with a hand that can’t stand the heat.
SPR is also a plan. At low SPR the commitment decision has to be made on the flop, because one more bet usually leaves you in a spot where folding is wrong on price alone — the expensive line there is bet-fold. At SPR 10 or more there are three streets of growing bets ahead, and one pair plays best as a pot-control hand: bet or call for one or two streets, then slow down when the action says you are beaten. Sets and two pair are the other way round: at high SPR they need to start building the pot early. Tournament stacks and 3-bet pots make SPR low by default.
Worked example
FAQ
What is a low vs high SPR?
Roughly: under 4 is low (commit with top pair and overpairs), 4–10 is medium, and 10+ is high (favor pot control and implied-odds hands).
How do you control SPR?
Preflop: 3-betting and 4-betting build the pot and lower SPR; flat-calling keeps the pot small and SPR high. Choose the SPR that suits your hand class.