What were the odds he hit that?
Count the cards that would complete the hand — the outs — and this gives you the exact chance of getting there, plus the odds-against that players usually quote. Settles most table arguments.
Two cards to come · 47 cards unseen
Pick the draw
9
Four to a flush, nine of the suit left
35.0%chance to hit
1.9 to 1against
65.0%miss
How the “rule of 4 and 2” compares
The usual shortcut is to multiply your outs by 4 with two cards to come, or by 2 with one. Here it gives 36% against the true 35.0% — off by 1.0 points.
Exact
35.0%
Rule of 4 / 2
36.0%
The shortcut drifts high as outs go up — at 15 outs it says 60% when the real number is 54%.
How the counting works: you know your two cards and the board, so after the flop there are 47 cards you haven’t seen and after the turn 46. Cards sitting in opponents’ hands stay in that unseen pool — one is exactly as unavailable to you as a card still in the deck, and you have no way to tell which is which.