Poker Odds Calculator (Texas Hold'em)

Count your outs and get the exact odds of hitting by the turn, the river, or either — compared against the rule of 2 and 4 — plus the pot odds math that turns a price into a decision.

Result

next card
by the river (both cards)
rule of 2 & 4 says
equity the pot price requires

How this calculator works

Count the cards that complete your hand — or pick a common draw from the preset list — and the calculator turns them into exact probabilities: the next card, and (from the flop) the chance of getting there by the river. The rule-of-2-and-4 estimate sits right beside the exact number so you can see precisely how much the shortcut flatters big draws.

Add the pot and the bet you're facing, and the pot-odds line completes the decision: the price expressed as required equity, and whether your draw clears it — with the flop-street subtlety handled honestly. A call that sees both cards (an all-in) gets judged against the by-river number; a call that buys only the turn gets judged against the single-street number, with implied odds noted as what must cover any gap.

The formula

Unseen cards after the flop: 52 − 2 (yours) − 3 (board) = 47

P(hit the turn)  = outs ÷ 47
P(hit the river) = outs ÷ 46
P(by the river)  = 1 − (47 − outs)(46 − outs) ÷ (47 × 46)

Required equity  = call ÷ (pot + call)
Rule of thumb: outs × 2 per street, × 4 for both

Pure combinatorics — every unseen card equally likely — as taught in any probability course and applied to hold'em in MIT OpenCourseWare's 15.S50 Poker Theory and Analytics. The pot-odds framework is David Sklansky's The Theory of Poker. The preflop matchup equities below come from exhaustive enumeration of all possible boards — the standard computation every equity tool reproduces.

Classic preflop all-inEquityNickname
Pair vs two overcards (22 vs AK)≈ 53 : 47the coin flip
Higher pair vs lower pair (AA vs KK)≈ 82 : 18the cooler
Pair vs one overcard (KK vs AK)≈ 70 : 30dominated, with outs
Shared high card (AK vs AQ)≈ 74 : 26domination
Two overcards vs two undercards (AK vs 87)≈ 62 : 38the race that isn't

Worked example

You flop a flush draw (9 outs) and face a $20 bet into an $80 pot (the defaults):

  1. Unseen cards: 47. Next card: 9 ÷ 47 = 19.1%
  2. By the river: 1 − (38 × 37)/(47 × 46) = 1 − 0.650 = 35.0% (rule of 4 says 36 — close)
  3. Pot price: 20 ÷ (80 + 20) = 20% required equity
  4. Facing an all-in: 35.0% ≥ 20% — clear call
  5. Facing one street of betting: 19.1% vs 20% — a hair short on direct odds, and implied odds (the money you win when the flush arrives) close the gap easily here

That last line is the whole craft in miniature: the same draw, the same price, and the answer turns on what your call actually buys.

Assumptions & tips

  • Discount dirty outs before trusting clean math. A straight card that also completes an opponent's flush is not a full out. Exact probability applied to the wrong outs count is precision without accuracy.
  • Memorize three numbers: flush draw 35%, open-ended straight 31.5%, gutshot 16.5% — all by the river. Most in-game arithmetic is one of these plus pot odds.
  • Pot odds price the call; implied odds price the future. Deep stacks make marginal draws profitable; short stacks make them folds. The pot in front of you is never the whole pot you're playing for.
  • The coin-flip table prices all-ins. Knowing that a dominated ace is a 3:1 dog changes how casually you call shoves with AQ — the preflop matchups are the tax table of tournament poker.
  • The math is the entertainment budget's friend. Odds tell you the cost of your decisions; they promise nothing about tonight. Play stakes whose swings you can genuinely afford.

Frequently asked questions

What exactly counts as an "out"?

An unseen card that upgrades your hand to (probably) the best one. A flush draw has nine: thirteen of your suit minus the four you can see. The craft is discounting dirty outs — cards that complete your straight but pair the board for someone's full house, or make your flush while making a bigger one possible. Serious players count 8 "clean" outs where a beginner counts 9; the calculator's math is exact, but the outs you feed it are a judgment call.

How accurate is the rule of 2 and 4?

Good enough at the table, and this page shows exactly how good. Multiplying outs by 4 (seeing both turn and river) tracks the true probability within about a point up to 9 outs, then drifts optimistic — 15 outs is really 54 percent, not 60. The rule of 2 for a single street stays accurate throughout. Use the rule live, use the exact numbers to calibrate it between sessions.

What are pot odds, in one breath?

The price the pot offers you: the call amount divided by what the pot will total after your call. Facing $20 into an $80 pot, you invest 20 of the eventual 100 — 20 percent — so the call is profitable whenever your chance of winning beats 20 percent. Pot odds turn "should I call?" from a feeling into a comparison between two percentages.

When do I use the by-river number versus the next-card number?

Match the equity to what your call buys. Facing an all-in on the flop, you see both cards — use the by-river probability. Calling a flop bet with more betting ahead buys only the turn card — use the single-street number, and fold in the extra money you might win later (implied odds) or lose to another bet. Using the 4-rule while facing only one street is the most common pot-odds mistake there is.

Are the preflop matchup numbers exact?

Yes — the classic matchup equities come from exhaustively dealing every possible board, a standard computation reproduced identically by every poker equity tool. A pair versus two overcards is the famous coin flip at roughly 55:45; a dominated ace is a 3:1 underdog. They are worth memorizing because they price nearly every all-in you will ever face.

Sources

  1. 15.S50 Poker Theory and Analytics, Lecture 3: Basic Strategy — Kevin Desmond, MIT Sloan School of Management; MIT OpenCourseWare, January IAP 2015. ocw.mit.eduThe course named in this page's formula section, and specifically the lecture that states the three things this calculator puts side by side: counting outs, the pot-odds call rule (win% must exceed call ÷ total pot after the call), and the rule of 2 or 4.
  2. Phil Gordon's Little Green Book: Lessons and Teachings in No Limit Texas Hold'em — Phil Gordon, Simon Spotlight Entertainment, 2005. ISBN 978-1-4169-0367-3. The source the MIT lecture above credits for the rule of 2 or 4 — the shortcut this page displays beside the exact combinatorial odds so you can see where it drifts optimistic. Cited bibliographically: no free full text to link.
  3. The Theory of Poker — David Sklansky, 4th edition, Two Plus Two Publishing, 1999. ISBN 978-1-880685-00-6. The pot-odds framework named in this page's formula section: pricing a call against your chance of winning, and the implied-odds extension the result line invokes when a draw falls short on direct odds. Cited bibliographically: no free full text to link.
  4. The Mathematics of Poker — Bill Chen and Jerrod Ankenman, ConJelCo, 2006. ISBN 978-1-886070-25-7. Chapter 4, "Playing the Odds: Pot Odds and Implied Odds", for the pricing rule this calculator applies, and chapters 7 and 8, "Playing Accurately: Cards Exposed Situations" and "Hand vs. Distribution", for the equity framework the all-in matchup table above assumes. Cited bibliographically: no free full text to link.
  5. Introduction to Probability — Charles M. Grinstead and J. Laurie Snell, 2nd edition, American Mathematical Society, 2003; freely redistributable edition dated 2006. math.dartmouth.eduChapter 3 combinatorics and card-dealing probability for the exact drawing odds from 47 and 46 unseen cards, including the complement rule that turns two missed streets into the by-the-river number.
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