Poker Math Cheat Sheet: Numbers to Keep Handy

This is the poker math worth keeping in your head — the outs-to-percentage conversions, pot-odds break-evens, and preflop matchups that come up hand after hand. Every number below is verified from real combinatorics, not rounded folklore. Learn the tables away from the table, and the arithmetic becomes automatic when a decision is on you.

Outs to percentage (flop with two cards to come)

The chance a given number of outs improves by the river, plus the rule-of-4-and-2 estimate so you can see how close the shortcut is.

Outs	Draw example	True % by river	Rule of 4
4	Gutshot straight	16.5%	16%
6	Two overcards	24.1%	24%
8	Open-ended straight	31.5%	32%
9	Flush draw	35.0%	36%
12	Flush + gutshot	45.0%	48%
15	Flush + open-ender	54.1%	60%

The rule tracks well up to about eight outs, then starts to overshoot. With 15 outs, trim the estimate by several points.

Outs to percentage (turn to river, one card)

Only one card left, so use the rule of 2. These are exact to a fraction.

Outs	Draw example	True % on river	Rule of 2
4	Gutshot	8.7%	8%
8	Open-ended	17.4%	16%
9	Flush draw	19.6%	18%
15	Combo draw	32.6%	30%

Pot-odds break-evens

The share of the time you must win for a call to break even, by bet size relative to the pot. The formula is call ÷ final pot, where the final pot already includes your call.

Bet size	You call…	Final pot	Win % needed
Quarter pot	0.25	1.5	17%
Third pot	0.33	1.66	20%
Half pot	0.5	2.0	25%
Two-thirds pot	0.67	2.34	29%
Full pot	1.0	3.0	33%
Double pot	2.0	5.0	40%

Clean anchors to memorize: half pot = 25%, two-thirds = 29%, full pot = 33%, double pot = 40%. More detail lives in the pot odds guide.

Preflop matchups

Common all-in situations, heads-up, equity for the favorite (rounded).

Matchup	Type	Favorite equity
AA vs KK	Pair over pair	82%
AA vs AKs	Pair vs its own ace	88%
AK vs QJs	Overcards vs two lower	60%
AK vs 22	Overcards vs pair (“coin flip”)	52%
KK vs AK	Pair vs overcard	70%
99 vs 22	Pair over pair	82%

The classic “race” — a pair versus two overcards — is roughly 52/48 in the pair’s favor, close enough to call a coin flip.

Being dealt specific hands

Straight from the 1,326 possible starting combos.

You are dealt	Chance
A specific pair (e.g. AA)	0.45% (1 in 221)
Any pocket pair	5.9% (1 in 17)
A specific suited hand (e.g. AKs)	0.30% (1 in 331)
Any two suited cards	23.5%
AK (suited or offsuit)	1.2% (1 in 83)

Flopping key hands

What your starting hand is likely to become on the flop, straight from the combinatorics.

You hold	You flop…	Chance
A pocket pair	A set or better	11.8% (about 1 in 8)
Two suited cards	A flush draw	10.9%
Two suited cards	A made flush	0.8%
Any two cards	At least a pair (using a hole card)	~32%
Two unpaired cards	An open-ended or better straight draw (connectors)	~10%

The set number is the famous one: with a pocket pair you flop a set roughly 1 time in 8, which is why small pairs are usually played to “flop a set or fold.”

Improving from flop to river

Once you have a draw on the flop, these are the odds it completes by the river — the same figures as the outs table, framed by draw.

Flop draw	Outs	Completes by river
Gutshot	4	16.5%
Two overcards	6	24.1%
Open-ended straight	8	31.5%
Flush	9	35.0%
Flush + gutshot	12	45.0%
Flush + open-ended	15	54.1%

The formulas behind the sheet

• Outs to percentage: rule of 4 and 2, or exact 1 − (unseen − outs choose 2) ÷ (unseen choose 2).
• Pot odds needed: call ÷ final pot.
• Combos of a hand: pair = 6, suited = 4, offsuit = 12, any unpaired = 16.
• Any pocket pair dealt: 6 × 13 ÷ 1326 = 5.88%.

Keep this page open while you study, and cross-check the fuller poker odds chart. Once the numbers are memorized, apply them in real Texas Hold’em hands and revisit the odds and math hub for the reasoning behind each figure.