I don't like raising folks with draws on the flop - certainly below $200 NL - at lower stakes they just don't slow down if you get into a pissing match with them, they were pfr and they hit any piece of flop (or have overs).
On the flop you almost always have implied odds to call to see up to a 3/4 pot bet with a draw esp vs an aggro player- you have position so call and see what they do on the turn.

If you miss and they bet out 3/4 - full pot again you can fold usually.

If they slow down they often were just firing out a CB into you on the flop or a scare card dropped on the turn - that is the time to take them off it with a pot sized bet (if checked to) or pot sized raise of weak lead.

River gets scary if you don't hit your draw.
If they call a big turn bet from you and you miss you then have to decide to either give it up or fire again on river - if there is a flush draw out there that didnt get home on the river and they keep making weakish leads on flop and turn and make another on the river they may well have a missed flush draw and it's worth firing again (a 1/2-2/3 pot bet should be enough to take them off if they missed their own draw)...otherwise you have a tough decision to make..

btw..how do u turn A2-A9s into profitable play if u call a raise of 4bb on button?>


you don't unless you are deep-stacked or can guarantee a multi-way pot - Axs is not a hand you really want to play isolated even with position against a raising player unless he is very weak post-flop

My guess is because everything is so situationally dependent you will just be screwing yourself by trying to find a 'magic number'. I say that because the 'magic number' would either wind up being incorrect far too often or it would become a 'magic range of numbers' that would have to be too large to be correct to make it useful.

It might be more useful to look at it from the POV of protecting a hand. Say you have JJ and the board comes J73r. There are 6 hands with gutshots. If there is 150 in the pot and your stack is 880 you probably need to think about protecting your whole stack as well as the pot amount because there are a number of scenarios where you will go AI (assume your opponent covers). You take the amount you want to protect (1,030) and divide it by his odds (he is 10.5:1 against hitting his gutshot). He gets proper odds on bets less than 98 so you want to bet say, 105-120 to make it a mistake for him to call.

With a draw you do the reverse. You estimate what you will win in addition to the pot if you hit, find the break even point, and then call/fold (raise is also possible of course, but for simplicity I'll ignore it.). If someone could write a program to do this in the 30 sec you generally have to make a decision online they would probably make some $. Even that program would be restricted by the users ability to estimate the amount his opponent was willing to lose on a given hand.

I got a number of these formulae from a book I purchased recently. If you are interested in the book's title PM me and I'll forward it. That will keep me from being a 'spammer'.

lol cal - I doubt anyone is going to accuse you of spam if you just post the name of a poker book!