Stack-to-Pot Ratio (SPR) Calculator
Calculate the Stack-to-Pot Ratio (SPR) for a poker hand. SPR is a key metric used in No-Limit Hold'em to guide post-flop decisions.
Enter the Effective Stack Size (the smallest stack involved in the pot) and the Current Pot Size (total chips currently in the pot before any action on the current street).
Enter Hand Details
Understanding Stack-to-Pot Ratio (SPR)
What is SPR?
SPR stands for Stack-to-Pot Ratio. It's calculated at the start of a street (most commonly the flop) by dividing the effective stack size by the size of the pot. The effective stack is the smaller of the two stacks involved in the hand.
SPR helps gauge how committed players are to the pot relative to their remaining chips. A high SPR means a player has a lot of chips left compared to the pot, allowing for more maneuverability and bluffing. A low SPR means players have relatively few chips left, making it harder to fold and often indicating a commitment to playing for stacks.
SPR Formula
The formula for SPR is simple:
SPR = Effective Stack Size / Current Pot Size
Both values should be measured in the same unit (e.g., chips, big blinds, dollars).
Why SPR Matters
SPR is a crucial factor in deciding how to play hands, especially on the flop:
- Low SPR (e.g., 3 or less): Often indicates a hand where players are likely committed to getting all their chips in. Big pairs and strong top-pair hands are often good in low SPR situations. Implied odds hands (like small suited connectors) are less profitable.
- Medium SPR (e.g., 4 to 8): These are common SPRs where decisions are more nuanced. Top pair is strong but not necessarily an all-in hand without improvement or favorable board textures. Drawing hands have better implied odds.
- High SPR (e.g., 9 or more): Players have many chips behind. Big pairs are less valuable without improvement as players won't pay off big bets easily. Strong drawing hands (like flush draws and open-ended straight draws) and hands that can make nut straights or flushes gain significant value due to high implied odds. Bluffing and complex maneuvering become more viable.
SPR Examples
Click on an example to see the calculation:
Example 1: Low SPR (Pre-flop shove)
Scenario: Hero has 500 chips, Villain has 450 chips. The pot is 150 chips (after blinds and pre-flop raises).
1. Known Values: Effective Stack = min(500, 450) = 450 chips, Pot Size = 150 chips.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 450 / 150
4. Result: SPR = 3.0
Conclusion: This is a low SPR. Players are likely committed if they have even moderately strong hands.
Example 2: Medium SPR (Standard raised pot)
Scenario: Hero and Villain both started with 100 big blinds (10000 chips). Pre-flop, Hero raised to 300, Villain called. Pot size on the flop is 650 chips (300 + 300 + 50 small blind/big blind initial bets).
1. Known Values: Effective Stack = 10000 - 300 = 9700 chips, Pot Size = 650 chips.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 9700 / 650
4. Result: SPR ≈ 14.92
Conclusion: This is a high SPR. Big pairs are vulnerable, drawing hands and hands that can make the nuts gain value.
Example 3: Low SPR (After a smaller raise and call)
Scenario: Effective Stack = 20 big blinds, Pot Size = 10 big blinds.
1. Known Values: Effective Stack = 20, Pot Size = 10.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 20 / 10
4. Result: SPR = 2.0
Conclusion: Very low SPR. Shoving or calling shoves with a wide range is common here.
Example 4: Medium SPR (Multiway pot)
Scenario: Three players see a flop. Effective Stack (smallest stack among the three) = 80 big blinds. Pot Size = 30 big blinds.
1. Known Values: Effective Stack = 80, Pot Size = 30.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 80 / 30
4. Result: SPR ≈ 2.67
Conclusion: Low SPR. Especially tricky in multiway pots, often favoring hands that don't need much protection.
Example 5: High SPR (Limped pot)
Scenario: Hero and Villain both have 100 big blinds. They just limp into the pot (no raise). Pot size on the flop is 2 big blinds.
1. Known Values: Effective Stack = 100 big blinds, Pot Size = 2 big blinds.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 100 / 2
4. Result: SPR = 50.0
Conclusion: Extremely high SPR. Only the absolute nuts should play for stacks here. Implied odds are massive.
Example 6: SPR after a bet on the flop
Scenario: Pot size on the flop was 650 chips. Villain bet 400 chips, Hero called. Now calculate SPR for the *turn* street (assuming no one shoves).
1. Known Values: Suppose Hero's remaining stack is 9300 chips after calling 400. Villain's remaining stack is 9300 chips after betting 400. Effective Stack for turn = 9300 chips. Pot size on turn = 650 (flop pot) + 400 (Villain bet) + 400 (Hero call) = 1450 chips.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 9300 / 1450
4. Result: SPR ≈ 6.41
Conclusion: This is a medium SPR situation going into the turn.
Example 7: SPR when one player is very short-stacked
Scenario: Hero has 5000 chips, Villain has 800 chips. Pot size on the flop is 700 chips.
1. Known Values: Effective Stack = min(5000, 800) = 800 chips, Pot Size = 700 chips.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 800 / 700
4. Result: SPR ≈ 1.14
Conclusion: Very low SPR. Villain is nearly pot-committed regardless of their hand strength on the flop.
Example 8: SPR in a 3-bet pot
Scenario: Hero and Villain both start with 100 big blinds. Hero raises to 3 BB, Villain 3-bets to 10 BB, Hero calls. Pot size on the flop is ~20.5 BB (10 + 10 + 0.5 rake/blinds representation).
1. Known Values: Effective Stack = 100 BB - 10 BB = 90 BB, Pot Size ≈ 20.5 BB.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 90 / 20.5
4. Result: SPR ≈ 4.39
Conclusion: This is a medium SPR situation, typical of 3-bet pots.
Example 9: High SPR after a small flop bet
Scenario: Pot size on the flop was 10 BB. Effective stack for both players was 95 BB. Player A bets 3 BB, Player B calls. Calculate SPR for the turn.
1. Known Values: Effective Stack for turn = 95 BB - 3 BB = 92 BB. Pot size on turn = 10 (flop pot) + 3 (bet) + 3 (call) = 16 BB.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 92 / 16
4. Result: SPR = 5.75
Conclusion: Still a medium/high SPR situation on the turn, indicating lots of playability.
Example 10: SPR when effective stack is exactly the pot size
Scenario: Effective Stack = 500 chips, Pot Size = 500 chips.
1. Known Values: Effective Stack = 500, Pot Size = 500.
2. Formula: SPR = Effective Stack / Pot Size
3. Calculation: SPR = 500 / 500
4. Result: SPR = 1.0
Conclusion: Very low SPR, suggesting players are all-in or pot-committed with almost any pair or strong draw.
Frequently Asked Questions about SPR
1. What is SPR in poker?
SPR stands for Stack-to-Pot Ratio. It's the ratio of the effective stack size to the current size of the pot, calculated typically at the start of a street, most commonly the flop.
2. How do I calculate SPR?
Divide the effective stack size by the pot size. Both values must be in the same unit (e.g., chips or big blinds). SPR = Effective Stack / Pot Size.
3. What is the "Effective Stack Size"?
The effective stack is the smaller of the two stack sizes belonging to the players involved in the hand. This is the maximum amount of chips that can be won or lost by either player in that specific hand.
4. When is SPR usually calculated?
SPR is most commonly referenced for the flop, as it significantly influences decision-making on subsequent streets (turn and river). However, you can calculate it at the start of any street.
5. Why is SPR important?
SPR provides context for post-flop play. It helps players determine hand values, assess implied odds, plan betting lines, and decide whether to play for stacks or make smaller bets.
6. What is considered a "low" SPR?
Generally, an SPR of 3 or less is considered low. In these situations, players are often pot-committed with a wide range of hands.
7. What is considered a "high" SPR?
An SPR of 9 or more is typically considered high. High SPR hands are more about playing for implied odds and making strong, hidden hands (like flushes or straights).
8. How does SPR affect hand strength?
The required hand strength to play for stacks changes with SPR. In low SPR spots, one pair is often sufficient. In high SPR spots, you usually need two pair, trips, or a strong draw to commit your stack profitably.
9. Can SPR change during a hand?
Yes. While SPR is usually calculated at the start of the flop, the ratio of remaining stack to pot changes after each bet and call on the flop, turn, and river. Recalculating it at the start of each street gives you the relevant SPR for that street.
10. Is SPR only for No-Limit Hold'em?
SPR is most relevant and widely discussed in No-Limit Hold'em because players can bet any amount, including their entire stack, which makes stack sizes relative to the pot crucial. It's less applicable in Limit or Pot-Limit games where bet sizes are capped or directly tied to the pot size.
