Odds · Beginner

Basic odds: outs and the rule of 2 and 4

Count your outs, turn them into a percentage in your head, and compare it with the price of a call.

2 min readAlso available in:繁體中文简体中文

On this page

You don’t need to be good at maths to use odds at the table. Three steps cover almost every decision with a drawing hand: count outs, estimate your chance, compare it with the price.

Step 1: count your outs

Outs are the unseen cards that turn your hand into the likely winner.

HandA10
BoardK72
Flush draw13 hearts in the deck, 4 already visible: 9 outs.
DrawOuts
Flush draw (four to a flush)9
Open-ended straight draw (e.g. 8-9-10-J)8
Two overcards (e.g. A-K on a low board)6
Gutshot straight draw (e.g. 8-9-J-Q, needs a 10)4
Pocket pair hoping for three of a kind2
Flush draw + open-ended straight draw15

Step 2: the rule of 2 and 4

  • On the flop, with two cards to come (you’ll see both turn and river): outs × 4 ≈ your chance in %.

  • On the turn, with one card to come: outs × 2 ≈ your chance in %.

  • Only use × 4 if you will really see both cards — if you face a big bet on the turn too, use × 2 on each street.

OutsFlop → river (exact)Rule of 4Turn → river (exact)Rule of 2
28.4%8%4.3%4%
416.5%16%8.7%8%
624.1%24%13.0%12%
831.5%32%17.4%16%
935.0%36%19.6%18%
1245.0%48%26.1%24%
1554.1%60%32.6%30%

Exact figures assume your outs are among the 47 unseen cards on the flop (46 on the turn).

Step 3: compare with the pot odds

Pot odds tell you how often you need to win for a call to pay off: divide the call by the total pot after you call.

StepExample
Pot before the bet100
Opponent bets50
You need to call50
Pot after your call100 + 50 + 50 = 200
You need to win at least50 ÷ 200 = 25%

On the turn with a flush draw, you have about 18–20%. That’s less than 25%, so calling this bet loses chips in the long run — unless you expect to win extra when you hit. With the same draw on the flop and no more bets to come, 35% beats 25%: call.

More on this topic