Math

What are outs in poker, and how do you count them?

Outs are the unseen cards that will improve your hand to one that's likely to win. A flush draw has 9 outs, an open-ended straight draw 8, a gutshot 4, two overcards 6. Multiply outs by 2 for the chance on the next card and by 4 for two cards to come.

Example:Open-ended straight draw = 8 outs ≈ 17% on next card, ≈ 32% by river.

Why it matters

Counting outs is how you estimate equity at the table without a calculator. The two refinements that matter: discount outs that also help the opponent (a flush card that pairs the board when they might have a set), and add outs for backdoor draws only when there are two cards to come.

Then the arithmetic: outs give equity, the pot gives the price, and the comparison gives the decision.

The numbers

  • Exact by-the-river odds from the flop: 4 outs 16.5%, 6 outs 24.1%, 8 outs 31.5%, 9 outs 35.0%, 12 outs 45.0%, 15 outs 54.1%.
  • On the turn (one card to come): 4 outs 8.7%, 8 outs 17.4%, 9 outs 19.6%, 15 outs 32.6%.

Figures come from the same preflop charts and research data the rest of the site uses (charts last updated July 5, 2026); they change when that data does.

See it on the chart
Outs & odds chart

Exact turn, river and by-the-river odds for 1–20 outs.

The leak it maps to
Weak equity intuition

You can't quickly estimate equity vs typical ranges, leading to bad bluff-catch and bluff decisions.

Common questions

How many outs does a flush draw have?

Nine — the thirteen cards of the suit minus the four you can see (two in your hand, two on the board). That's about 35% to complete by the river from the flop, 19.6% on the next card.

What is the rule of 2 and 4?

Multiply your outs by 2 for the approximate chance of hitting on the next card, or by 4 for the chance by the river with two cards to come. It's accurate to within a couple of percent up to about 8 outs.

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