Is there a "Rule of 20" for flush draws (implied odds)

Let's say you have a flush draw on the flop.
(You have 2 spades, and flop has 2)

Usually, pot odds and pot equity (outs) says calling a flush draw is not good.

So, let's discuss implied odds.
I mainly hear this talked about for set mining.
You only call if the stacks are 20x the call. (Rule of 20)

Does the Rule of 20 apply to a flush draw?
If the call amount is $50, then stacks need to be $2000 to call?
In a cash live game of 1/2NL (200NL), most stacks are about $200 or 100BB.

Anyway yes, Its just saying profitable call if the stack is deep.

Not just one party but both stacks of course.

Well, how deep is deep?
Is there a general formula?

Rule of 20 is for setmining preflop and you are talking about a postflop scenario.

Anyway, if you flop a flush draw you have a ~18% chance of hitting on the turn, so even without considering implied odds you only need slightly better than 4:1 direct odds to correctly call. So stacks certainly don't need to be as deep as 20x the call amount...as long as the pot is 4-5x as big as the call amount you're not making a mistake.

Unfortunately, you're almost never getting 4:1 (raise of 33% of pot)
So, a flush draw call is never that simple.

RickAversion said:

Unfortunately, you're almost never getting 4:1 (raise of 33% of pot)
So, a flush draw call is never that simple.

Click to expand...

as you are only getting 3/1 then you consider implied odds, how loose is your opponent will he call if you hit.
Also do you have other outs like over cards and you can always try to bluff if you dont hit, just because your oppoent bets doesnt mean he has anything