What is SPR in Poker?

SPR is stack-to-pot ratio: the effective stack divided by the current pot. After the flop, an SPR around 4 or less is low — you are closer to getting stacks in. Double-digit SPR is high: there is room to fold, float, or barrel later. SPR is a ratio, not a bet size.

Work one number. Pot is 6bb on the flop, 100bb effective behind: SPR is about 16. Pot is 25bb on the flop, 100bb behind: SPR is 4. A 3-bet pot is smaller SPR than a single-raised pot with the same starting stacks, because more money is already in the middle.

The next bet changes SPR. If you c-bet half pot, both the pot and the remaining stacks move. Do not freeze the flop SPR for the river.

What SPR is

• Effective stack divided by the pot.
• Low after the flop: about 4 or less. High: double digits.
• A 3-bet pot has a lower SPR than a single-raised pot at the same starting stack.

How to calculate SPR

Round bb, labeled as examples. These are not solver frequencies.

SPR uses the shorter stack. If you have 150bb and they have 80bb, use 80.

Low vs high SPR

Low SPR favors getting stacks in with strong made hands and some draws. High SPR favors more folding, more bluffing later, and less "I have top pair so I stack off."

Do not copy an UTG-versus-button open table here. SPR is not a seat chart.

3-bet pot vs single-raised pot

Same 100bb start: a 2.5bb open plus a call is a small pot and a high flop SPR. A 3-bet to 9bb plus a call is a large pot and a low flop SPR. The same top pair plays differently in those two pots.

Do not treat SPR as a reason to always stack off. A low SPR with eight-high is still a fold. Do not write a linear-versus-polar 3-bet lecture here.

Example spots

1. Take: A low-SPR spot where you should commit.

You are on the button with top pair, top kicker on a 9♠ 7♦ 2♣ flop. The pot is 20 bb and the effective stack is 40 bb. SPR = 40 / 20 = 2. That is a very low SPR. With top pair and a pot that is already half your stack, you are not folding. You bet 10 bb and call a shove. The low SPR means you are pot-committed with any hand that beats the board, and top pair is well ahead of most draws and worse pairs. You are not looking for a fold; you are looking to get the rest in.

2. Don't: Stacking off just because SPR is low.

You defend your big blind with 8♣ 6♣ against a raise. The flop comes A♠ K♦ 2♥. The pot is 15 bb and the effective stack is 30 bb, so SPR = 2. That is low, but your hand is nothing but a busted draw and two overcards that are not even to the board. Low SPR does not mean you must commit with any two cards. You check and fold to a bet. The low SPR only matters when your hand has equity or showdown value; here it does not, so you let it go.

When SPR is not enough to stack off

Low SPR is a green light to commit only when your hand is strong enough to win at showdown or has enough equity to justify the call. It is not a license to stack off with air or marginal holdings.

• When you have a draw that is not getting the right price. In a low-SPR pot, you may be forced to call an all-in with a flush draw, but only if the pot odds justify it. If SPR is 2 and your opponent shoves, you are getting about 2:1 on your call. A flush draw with one card to come has about 20% equity, so you need at least 4:1. Low SPR does not change that math.
• When your opponent's range crushes your hand. If the board is coordinated and your opponent is representing a set or two pair, a low SPR does not mean you have to pay them off. You can still fold if the evidence says you are beat.
• When you are multiway. SPR is calculated on the effective stack, but in a multiway pot the actual risk is higher because another player can still raise. A low SPR heads-up may be a commitment spot, but with two opponents left to act, you need a stronger hand to commit.
• When the next bet changes SPR. SPR is a snapshot. If you bet and get raised, the pot grows and the effective stack shrinks, so the SPR on the next street is even lower. That can force you to commit with a hand that was not strong enough at the original SPR. Do not assume the current SPR is the one you will face on the turn.

The next bet changes SPR

If they bet the flop, remaining stacks fall and the pot grows, so SPR on the turn is lower. Recalculate before you decide to get it in. A flop SPR of 8 can become a turn SPR of 2 after one pot-sized bet.

If you jam over a small bet, you are choosing to play this SPR, not the old one. Do not ignore that the next bet changes SPR.

If your opponent continues after you bet in a low-SPR pot, the decision is usually binary: call the all-in or fold. There is rarely a raise left because the stack is too short. Evaluate your hand's equity against the range that would continue. If you have a made hand that beats most of that range, call. If you have a draw, compare the pot odds to your equity. If you have nothing, fold. In a high-SPR pot, a continuation bet does not commit you; you can still fold to a raise if your hand is weak.

Common mistakes

• Treating SPR as a bet size. SPR is a ratio, not a number of chips to bet. Betting a fixed fraction of the pot regardless of SPR ignores the commitment reality.
• Ignoring the effective stack. SPR uses the smaller of your stack and your opponent's. If you have 100 bb and your opponent has 20 bb, the SPR is based on 20 bb, not 100. Overestimating SPR leads to overfolding or underbetting.
• Assuming low SPR always means stack off. Low SPR only means you are closer to being pot-committed. It does not mean you must commit with any hand. You still need a hand worth committing.
• Forgetting that SPR changes on later streets. After a flop bet, the pot grows and the effective stack shrinks, so the turn SPR is lower. Players who plan only for the flop SPR often find themselves accidentally committed on the turn.
• Using SPR in multiway pots without adjustment. SPR is a heads-up concept. In multiway pots, the presence of other players increases the risk, so you need a stronger hand to commit at the same SPR.

Frequently asked questions

What is SPR in poker?

Stack-to-pot ratio: effective stack divided by the current pot. It is a ratio, not a bet size. How do you calculate SPR?

Take the shorter remaining stack, divide by the pot right now. Example: 100bb effective, pot 25bb after the flop → SPR 4. How does SPR change after a 3-bet pot?

In a 3-bet pot, the pot is larger relative to the stacks, so the SPR is lower. For example, if you raise to 3 bb, get 3-bet to 10 bb, and call, the pot is about 21 bb and the effective stack is 90 bb, giving an SPR of about 4.3. In a single-raised pot, the pot might be 7.5 bb with a 100 bb stack, giving an SPR of about 13. Lower SPR means you are more committed and should play more straightforwardly. What is a good SPR for a set-mining hand?

A common guideline is that you want an SPR of at least 10 to profitably set-mine, because you only flop a set about 12% of the time and need to win a big pot when you do. With a lower SPR, the implied odds are not there, so calling a raise with a small pair becomes less profitable. Does SPR matter more on the flop or the turn?

SPR matters on every street, but it is most useful on the flop because that is where you decide whether to commit your stack. On the turn, the pot is larger and the stacks are shorter, so the SPR is lower and the decision is often simpler: you are either committed or not. Many players use flop SPR to plan the whole hand.