Poker Outs & Equity Calculator (Rule of 2 and 4)
Enter your outs and the streets remaining to instantly get your chance of completing your draw: the Rule of 2/4 approximation, the exact hypergeometric probability and the error. Every figure is computed by lib/poker-math.ts.
Outs are the cards left in the deck that complete your hand. This calculator contrasts the shortcut with the exact probability so you can judge a drawing call.
- Approx equity (×4 / ×2)
- 36%
- Exact equity (hypergeometric)
- 34.97%
- Approximation error
- 1.03%
The Rule of 2 and 4 is a mental shortcut: multiply outs by 4 after the flop, by 2 after the turn. This page also shows the exact value and error.