Basics of pot odds

Am i correct, after the flop in Hold'em, to assume that calculating the chance of hitting outs is

no. of outs x2 + 1

on the turn and the same on the river

[AaronBrown]

That's about right. I wouldn't bother adding the 1.

The exact answer is number of outs divided by 47, since there are 47 cards you haven't seen. For example, with 9 outs for a flush you have 9/47 = 0.1914 = 19.14%. Your approximation gives 19%, which is accurate enough for Poker. But 18% is also accurate enough. The mental effort required to remember to add 1 would be better spent paying attention to the other players and double-checking that you've computed the outs correctly.

[Mr. Curious]

Rather than always trying to do the math, just create and memorize an "outs" table. It will save you time and let you focus on the game.