Poker Stack-to-Pot Ratio (SPR) Calculator
Calculate poker SPR and get strategic guidance for any street.
Find shove, raise, and fold thresholds based on stack-to-pot ratio for tournament and cash games.
Stack-to-Pot Ratio (SPR)
SPR is one of the most important strategic concepts in no-limit poker. It tells you how committed you are to a hand based on remaining stack relative to the pot.
The formula: SPR = Effective stack / Pot size
Where “effective stack” is the smaller of the two players’ remaining stacks at the start of the street.
SPR strategic ranges:
| SPR | Strategy |
|---|---|
| Under 1 (committed) | Almost always all-in profitable with any pair or strong draw |
| 1-3 (low SPR) | Top pair / overpair commits; play it like a 1-bet game |
| 3-6 (medium) | Top pair good, set/two pair very strong, slowplay rarely |
| 6-13 (medium-deep) | Sets and two pairs are key; bluff catchers value strong |
| 13-20 (deep) | Stack and pot management critical; avoid coin flips |
| Over 20 (very deep) | Implied odds dominate; strategy shifts heavily to position |
Why SPR matters:
- Commitment math: at SPR < 4, top pair often pot-commits
- Bluff frequency: higher SPR = more room to bluff or fold
- Stack preservation: deep SPR rewards postflop skill
- Tournament ICM: high SPR + bubble = tighten up significantly
Practical example: You raise to 3bb preflop with KK, called by one player. Pot = 7bb (3+3+1 from BB).
If both players have 100bb starting stacks, after preflop:
- Effective stack = 97bb
- SPR = 97 / 7 ≈ 14
This is “deep”, so KK should bet small to medium rather than shove. There’s plenty of room to extract value street by street.
If both players have 30bb (short stack):
- Effective stack = 27bb
- SPR = 27 / 7 ≈ 4
Now KK should be ready to commit on the flop with any non-ace flop. There’s not enough room to maneuver, so just get the money in.
Common SPR ranges by game:
| Game Type | Typical SPR Range |
|---|---|
| Tournament early (100bb starting) | 10-30 preflop, 5-15 by river |
| Tournament middle (30-50bb) | 4-10 preflop |
| Tournament late (15-25bb) | 1-3 preflop, push/fold range |
| Cash 100bb | 10-25 |
| Cash 200bb (deep) | 25-100+ |
| Cash 50bb (short) | 5-12 |
The “20-1” rule: Aim to 3-bet to 20% of effective stack when out of position to keep SPR around 4, which is where top-pair-or-better commits cleanly. Smaller raises create awkward postflop SPRs.
Multiway considerations:
SPR falls in multiway pots, and it falls hard. Every extra caller adds their money to the pot while your own stack stays exactly where it was, so the denominator grows and the numerator does not.
Compare the two. Heads-up at 100bb, that 3bb raise built a 7bb pot against a 97bb stack: SPR 13.9, deep enough to play three streets of poker. Add two more callers and the pot is 21bb while the stacks are 97: SPR 4.6. The same hand, the same stack, and you have gone from a deep-stack spot to a commitment spot without doing anything.
That is why one-pair hands play so badly multiway. You are far closer to being committed than the stack sizes suggest, and there are more opponents who might have beaten you.
Mistake patterns by SPR:
Low SPR (under 4):
- Mistake: not committing top pair
- Fix: any reasonable equity = jam
Medium SPR (4-10):
- Mistake: pot-committing with weak hands
- Fix: think 1-2 streets ahead about commitment math
High SPR (over 15):
- Mistake: getting all-in with one pair
- Fix: tighten up, focus on implied odds and big draws
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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