Poker math made simple: outs, odds, equity and EV

Step 1: count your outs

Outs are the unseen cards that give you the best hand. Common draws:

• Flush draw: 9 outs
• Open-ended straight draw: 8 outs
• Gutshot straight draw: 4 outs
• Two overcards: about 6 outs
• Flush draw plus open-ender: 15 outs

Be honest. Don’t count a card that pairs the board if it might give your opponent a full house.

Step 2: turn outs into a percentage

The rule of 2 and 4 is the table shortcut:

• One card to come: outs × 2
• Two cards to come (flop to river, with no more betting): outs × 4

A flush draw on the flop is about 9 × 4 = 36% to hit by the river. The exact figure is 35%. On the turn it is about 9 × 2 = 18% (exact 19.6%).

Step 3: work out your pot odds

Required equity = amount to call ÷ (pot after you call)

Example: the pot is 100 and your opponent bets 50. You call 50 to win a final pot of 200, so you need 50 ÷ 200 = 25% equity to break even.

With a flush draw facing that bet on the turn, you have about 19.6%. That’s less than 25%, so calling loses chips unless you expect to win more later (implied odds).

Step 4: think in expected value

EV = (chance to win × amount won) − (chance to lose × amount lost)

Calling 50 to win 150 with 30% equity: 0.30 × 150 − 0.70 × 50 = 45 − 35 = +10

A positive number means the call makes chips on average, even though you will lose it 70% of the time. Results in one hand don’t matter. The right decision, repeated, does.

Implied odds and fold equity

Two ideas adjust the raw maths:

• Implied odds: extra chips you expect to win on later streets when you hit. They are bigger with disguised draws and deep stacks.
• Fold equity: the chance your opponent folds to your bet. It is why semi-bluffing with draws is often better than calling.

Equity in all-in spots

When all the chips go in, only equity matters. Some benchmarks to remember:

• Overpair vs underpair (AA vs KK): about 82 / 18
• Pair vs two overcards (QQ vs AK suited): about 54 / 46, or 57 / 43 against offsuit AK
• Two overcards vs two undercards (AK vs 87): about 62 / 38
• Dominated hand (AK vs AQ): about 74 / 26

Test any match-up with our odds calculator.