SPR — Stack to Pot Ratio — Poker Term Explained

SPR = effective stack / pot at the start of the flop. The effective stack is the smaller of the two remaining stacks, because that is all anyone can actually win or lose. The pot is measured once the preflop betting is complete and the flop is dealt — not mid-street, and not after the flop bet goes in.

Two numbers, one moment in time. That is the whole calculation, and it is why SPR is a planning tool: you work it out before the flop action starts, and it tells you how many bets are left to play.

Example 1 — single raised pot. Blinds 1/2, you open to 6 from the button with 200 behind, the big blind calls with 194 behind. The pot on the flop is 13 (6 + 6 + 1 from the small blind). The effective stack is 194. SPR = 194 / 13 ≈ 14.9. Deep: one pot-sized bet on each street still leaves money over, so a single top pair is rarely worth stacking off.

Example 2 — 3-bet pot. Blinds 1/2, you open to 6, the big blind 3-bets to 22, you call. Both started with 100, so 78 remains behind each. The pot is 45 (22 + 22 + 1). SPR = 78 / 45 ≈ 1.7. Shallow: one bet and one raise puts the stacks in, and an overpair is usually a happy all-in.

Below 3: commitment territory. Top pair with a good kicker and overpairs are usually strong enough to get the money in, because your opponent cannot represent enough by the river to fold you off.

Between 3 and 6: the middle ground. Plan the hand over two streets rather than three, and think about which turn cards let you continue comfortably.

Above 10: implied-odds territory. Sets, suited connectors and nut draws gain value, while one pair loses it — there is simply too much money behind for a marginal hand to survive three streets of pressure.

These bands describe tendencies, not laws. Board texture, ranges and opponent behaviour override the number every time: a 2-SPR pot on a monotone board with a passive opponent is not an automatic stack-off.

With three or more players the pot is bigger relative to the stacks, so SPR drops — yet the hand strength needed to commit rises, because every extra opponent adds another range that can beat you.

Measure the effective stack against the shortest player you are still likely to play against, and treat a low multiway SPR as a reason to value the nuts more highly, not as an invitation to stack off with one pair.

Recalculating SPR after the flop bet has already gone in — the number is defined at the start of the flop and using a later figure inflates it.

Using your own stack instead of the effective stack, which overstates how much is really in play.

Treating a band as a rule and stacking off with top pair at SPR 2 on a board that smashes the caller's range.

Ignoring SPR preflop: your raise size is what sets it, so the decision to create a low or high SPR is made before the flop, not after.