Interactive tool
Outs & draw probability
Counting outs is only useful if the outs are actually clean. This calculator handles the arithmetic after you make that judgment.
Why the denominator changes
There are 47 unseen cards after the flop and 46 after the turn. With 9 clean outs, the exact chance to hit on the turn is 9/47 ≈ 19.15%; the chance to hit by the river across two cards is about 34.97%.
“Clean outs” is the hard part
A flush card can complete your draw while also completing a higher flush for an opponent. If an out does not reliably turn your hand into the winner, discounting it is more honest than feeding an optimistic count into a precise calculator.