Pot odds, equity, and SPR in English

Every call you make is a price. Every bet you face is a frequency. Every stack you take to the flop is a ratio. If you cannot name those three numbers, you are playing by feel, and feel is how a flush draw becomes a stack-off "because I had a lot of outs." This page is the arithmetic in the voice of a player who has to use it before the time bank expires. For the clickable version, use the pot odds tool. For the streets that generate the prices, see postflop fundamentals and c-bets and barrels.

Pot odds: the fraction that actually matters

You are facing a bet. The pot already has some chips. They put in more. You must put in the same amount to continue. Pot odds are the share of the future pot that you are being asked to contribute. If that share is smaller than your chance of winning (your equity), the call is profitable in a world with no future bets. If it is larger, the call is losing unless implied odds or a raise plan save it.

The clean formula when you face a single bet and you are considering a call:

That 25% is the sentence you should hear in your head. Not "I am getting two to one." Two to one is the same math in odds form (you risk 50 to win 150, 50:150 = 1:3, which is 25%), and people fumble the conversion under the lights. Percents do not fumble as often. If you like ratios, fine. If you freeze, use the percent and the calculator.

Another one, because one example is a slogan and two is a habit. Pot $80, they shove $80. Required: 80 / (80 + 2×80) = 80/240 ≈ 33.3%. You need 33%. A flush draw on the flop with one card to come is not 33% — wait, we will do equity next — and a flush draw on the turn with one card to come is about 19.6% if you have nine outs. That turn call is not close on pot odds alone. If you still call, you are calling implied odds or a read. Name which.

Equity is not "outs times two"

Equity is your share of the pot if all remaining cards were dealt now and both hands went to showdown. It is a percent against a hand or against a range. Nine outs to a flush on the flop with two cards to come is roughly 35% against a made hand that is not drawing dead on your flush. Nine outs on the turn with one card to come is 9/46 ≈ 19.6%. The "rule of two and four" (outs ×4 on the flop, outs ×2 on the turn) is a pocket approximation: 9×4 = 36, 9×2 = 18. Close enough to act. Not close enough to brag.

Same draw, turn is the two of clubs. Now you have a pair and a flush draw. They bet $50 into $100 again. One card to come. Flush is ~20%, plus three aces if an ace is good, plus the paired deuce that might already be good against a bluff. Against a range that is all value kings, you are in the neighborhood of 25–30% depending on whether the ace plays. Against a range that includes air, you have more. The 25% price is the floor. Your job is to know whether you are above it.

Outs are not equal. Nine flush outs are clean against a set only if the flush is the nuts and they cannot fill up. Against a set on a two-tone board, some of your "outs" make them a full house. That is why we count clean outs, not optimistic outs. A gutshot is four outs. Two overcards are six. A pair plus a gutshot is ten if the pair is good when it stays the pair, which it often is not. If you have to talk yourself into 15 outs, you do not have 15 outs.

Implied odds and reverse implied odds

Implied odds are the extra money you expect to win on later streets when you hit. Reverse implied odds are the extra money you expect to lose on later streets when you hit and you are still behind. Set-mining 22 against a UTG open is an implied-odds hand: you fold most flops, and when you flop a set you try to win a stack. Ace-Jack offsuit against that same UTG open is a reverse-implied hand: you flop top pair, you pay three streets, you lose to Ace-King. Pretty connectors in position have implied. Offsuit Broadway out of position has reverse. If you cannot say which one you are holding, you are about to discover it the expensive way.

Reverse implied, worked: you call a three-bet out of position with KJo. Flop comes K-8-4 rainbow. You check-call a c-bet. Turn brick, check-call. River brick, they jam. Your king-jack feels like a hero-call. Their range is AK, KK, 88, 44, and some AQ they gave up. You are getting a price, maybe 30%, and you do not have 30% versus that range. The flop call "because I hit" is what put you here. Reverse implied odds are just implied odds with the sign flipped, and they love medium-strength made hands out of position.

MDF is their problem, then sometimes yours

Minimum defense frequency is how often a defender must continue, by calling or raising, to make a bluff at a given size break even if that bluff has no equity when called. Formula: MDF = 1 − B/(P+B). Pot $100, bet $50: MDF = 1 − 50/150 = 66.7%. They must continue two times in three, or else pure air prints.

MDF is not your calling standard. Your calling standard is pot odds plus implied minus reverse plus a read. MDF is a check on whether a range is folding too much. If you fold 80% to a half-pot river, you are folding too much and they should bluff you more. If you call 90% of half-pot rivers, you are calling too much and they should stop bluffing, then value-bet thinner. Population at small stakes overfolds rivers and overcalls flops. That is not a contradiction. Different streets, different egos. Use MDF as a flashlight, not as a commandment. The barrel page walks this from the bettor's side.

SPR, commitment, and why top pair changes jobs

Stack-to-pot ratio is effective stack divided by pot. Measure it on the flop, before the first flop bet, unless you are mid-tree and you know you are measuring a later street. SPR tells you how many bets it takes to get the rest in, and therefore what kind of hand you need to be happy stacking off.

• SPR 13–20. Single-raised pot, 100bb. Top pair is a three-street puzzle. Sets want to get it in and sometimes fail. Draws have implied. You can fold top pair on a brutal river without it being a disaster.
• SPR 4–6. Three-bet pot, 100bb. Top pair is often a stack. Two streets get it in. Set-mining 22 is a lot worse. Check-raising the flop as a draw is a real line because the stack fits.
• SPR 1–2. Four-bet pot or a short stack. One more bet. Hands are polar. Medium pairs are bluff-catchers or jams. Pretty turns do not get three streets of theater.

Pot commitment is SPR plus equity plus the remaining bet sizes. You are committed when folding the rest is worse than calling given the price and your equity. You are not committed because you have already put money in. Sunk cost is not a poker statistic. If the pot is $200 and they jam $20, you need 20/240 ≈ 8.3%. Almost every draw, every pair, every ace-high calls. If the pot is $200 and they jam $400, you need 400/1000 = 40%. That is a different sport. Same "I came this far." Different fraction.

A street-by-street price, not a vibe

Six-max, $1/$2, $200 effective. You defend the big blind with 87s versus a button 2.5x. Pot $7 after the preflop call? Button $5, you $3 more plus $2 already, small blind folded: pot $5 + $3 + $1 SB + $2 BB = $11. Let's be clean.

Notice the pattern. Preflop was a 27%-ish defend versus a 2.5x (worked on the position page). Flop was a 21% call versus a small c-bet with a gutshot and a plan. Turn was the nuts. If you skip the flop fraction and always peel "because I have a draw," you will peel the 90-into-120 turn in the earlier box and wonder why the month is red.

Rake, multiway, and other quiet multipliers

Pot odds ignore rake until they should not. In a $0.50/$1 pot-limit-or-not cash game with a $5 cap, a $20 pot that you win after calling $8 might only net you $17 after the drop. Thin river bluff-catchers die first. If the call is barely above the 25% line in a raked pot, it is not above the line. Tournaments do not rake pots the same way; they rake the buy-in. Do not import cash-game "fold the thin one" into a bounty tournament where the extra prize is sitting in the all-in, and do not import MTT "I need chips" into a 100bb cash table with a 5% drop.

Multiway, your equity is against two ranges, not one. A 35% flush draw heads-up is not 35% against two players who both have a pair. You can still be getting a price if the pot is bloated and the bet is small. You can be drawing dead against a higher flush draw you did not count. Multiway implied odds go up when you have the nuts and position. Multiway reverse implied go up when you have second pair in the middle of the field. The formula does not change. The equity input does.

Put the fraction in the tank, then act

Before you call, say the percent out loud in your head: pot, bet, required equity, estimated equity, implied yes or no. Before you bluff, say the required fold frequency: risk over risk-plus-pot. Before you stack off, say the SPR. If you cannot say them, you are not in a close spot. You are in an uncalculated one. Close is allowed. Uncalculated is how a cooler gets the blame for a price you never computed.

Practice on the pot odds tool until 50 into 100 is instant. Then go back to the hands. The formula will not make you a solver. It will stop you from paying 40% for a 17% draw and calling it heart. Heart is for the river you already priced. Everything else is arithmetic, plus a range, plus the seat. If the seat is still the part that wobbles, starting hands and position is waiting, and it does not care how pretty your flush draw was.