SPR (Stack-to-Pot Ratio) measures how much money is left to play relative to the pot size. It's a simple but powerful tool: it tells you how strong you need to be to go all-in and whether it makes sense to build the pot with your current hand.
Understanding SPR eliminates many of the "should I bet or not?" doubts in postflop play because it gives you a concrete framework for evaluating your hand's commitment level.
1. What Is SPR and How to Calculate It
SPR is calculated at the start of postflop play (flop), before any further bets:
SPR = Effective Stack / Pot at the Start of the Flop
The effective stack is the smaller of the two stacks in play (it limits the maximum that can change hands).
Example
Hero stack: $200 · Villain stack: $150 → Effective stack = $150
Pot at flop: $30 → SPR = 150 / 30 = 5
With SPR 5 there are 5 times the current pot left to play.
SPR can also be influenced preflop: if you want to reach the flop with a low SPR (so you can commit with top pair), make a larger preflop raise.
2. Low SPR (less than 4): Commitment Territory
With a low SPR, the pot is already large relative to the remaining stacks. You're nearly committed mathematically.
Example: SPR = 2
Pot $80 · Effective stack $160 · You c-bet $50 · Opponent goes all-in ($110 more)
To win the final pot you need ~37% equity. With top pair+, calling is correct.
With SPR less than 4:
- ✓Top pair + good kicker: going all-in is correct
- ✓Overpair: commit almost always
- ✓Strong draws (flush draw or straight draw): semi-bluff all-in has good EV
- ✗Trying to control the pot with medium hands: few streets to maneuver
3. Medium SPR (4–13): The Judgment Zone
Most postflop hands occur in medium SPR ranges. Here you need more than just top pair to be comfortable committing your entire stack.
| Hand | SPR 4–6 | SPR 7–13 |
|---|---|---|
| Top pair good kicker | Generally commit | With caution |
| Two pair | Commit | Commit (board permitting) |
| Set/Trips | Commit | Commit |
| Flush/Straight draw | Semi-bluff viable | Depends on fold equity |
Real example: SPR ≈ 5.4
NL10 · raise to $0.25 · call · Pot = $0.55 · Remaining stacks $3
SPR = 3/0.55 ≈ 5.4 → Two pair: commit. Top pair weak kicker: be careful with raises.
4. High SPR (greater than 13): Deep Stack Play
With a high SPR, a lot of money is at stake and the consequences of each decision are enormous. You need very strong hands to commit your entire stack.
- →Top pair / overpair: just a bluff-catcher in many spots. Don't put it in the center of the pot.
- →Two pair+, sets, flushes, straights: hands with which you can build the pot.
- →Set mining becomes very profitable (excellent implied odds with deep stacks).
- →Small bet sizes gain importance to manipulate SPR in your favor.
Practical tip: manipulate SPR preflop
If you have KK and want to reach the flop committed, make a larger preflop raise to reduce SPR. If you have 55 and want implied odds for set mining, you prefer a small preflop pot.
Conclusion
SPR doesn't tell you what to do; it tells you how strong you need to be to do something. It's the bridge between pot size and stack depth. Internalizing it will save you from committing entire stacks with hands that don't justify it — and from losing value with hands that should go in the middle.