🎲 Outs & the rule of 4 and 2
count your cards, know your chances
An out is any unseen card that improves your hand to a likely winner. Counting outs and converting them to a percentage — using the “rule of 4 and 2” — lets you estimate your chances in seconds at the table. This lesson shows how to count and convert.
When your hand isn’t best yet, the question is: how likely is it to get there? Start by counting your outs — the unseen cards that would improve you to (probably) the winning hand.
The standards are worth memorising: a flush draw has 9 outs (13 of the suit minus your 4), an open-ended straight draw has 8 (4 cards on each end), a gutshot has 4, and two overcards fishing for top pair have about 6.
Then convert outs to a percentage with the rule of 4 and 2: on the flop, multiply outs by 4 for your chance by the river; on the turn, multiply by 2 for the last card. A flush draw on the flop: 9 × 4 ≈ 36%. On the turn: 9 × 2 ≈ 18%.
💡 Key idea: the rule is an approximation, and that’s fine — poker decisions need a good number fast, not a perfect number slowly.
Count the cards that make your hand. A flush draw has nine outs (13 of a suit, minus the four you can see). An open-ended straight draw has eight. The rule of 4 and 2 turns outs into odds: multiply outs by 4 on the flop (two cards to come) or by 2 on the turn (one card to come). Nine outs on the flop ≈ 36% to hit by the river; on the turn ≈ 18%.
The common mistakes are double-counting outs that also give your opponent a better hand, and counting outs that make you a second-best hand. A flush draw is clean; a bottom-pair “draw” often isn’t. And remember the rule is an estimate — good enough to decide, not exact. Pair it with pot odds (the next lesson) and you can answer the only question that matters: is this draw worth the price?
Questions
What is the rule of 4 and 2 in poker?
A shortcut for turning outs into a rough win chance: multiply your outs by 4 on the flop (two cards to come) or by 2 on the turn (one card to come). Nine outs ≈ 36% on the flop, 18% on the turn.
How many outs does a flush draw have?
Nine. There are 13 cards of each suit; with two in your hand and two on the board you can see four, leaving nine unseen cards that complete the flush.