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.

Poker Outs & Equity Calculator (Rule of 2 and 4)
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.

Example result page →