Outs & Equity Result (Rule of 2 and 4)
A shareable, indexable outs result page: the exact chance of completing common draws after the flop and the turn, with the approximation error. Every figure is computed by lib/poker-math.ts.
This page lists the exact chance of completing common draws. After the flop (two cards) use x4, after the turn (one card) use x2; the exact hypergeometric probability and error are shown alongside.
Common draw completion odds
| Draw (outs) | After flop (exact / error) | After turn (exact / error) |
|---|---|---|
| Combo draw (flush + straight)（15） | 54.12% / ±5.88% | 32.61% / ±2.61% |
| Flush draw（9） | 34.97% / ±1.03% | 19.57% / ±1.57% |
| Open-ended straight draw（8） | 31.45% / ±0.55% | 17.39% / ±1.39% |
| Gutshot straight draw（4） | 16.47% / ±0.47% | 8.70% / ±0.70% |
| Pair to set（2） | 8.42% / ±0.42% | 4.35% / ±0.35% |
The Rule of 2 and 4 is a mental shortcut; this table also shows the exact hypergeometric probability and the approximation error.
Open the interactive Outs & Equity Calculator