I was thinking about how to calculate the break even folding frequency after encountering a guy who would 3b oop and double barrel very often. He cant have a hand all that often here, and if I call flop with something like OESD and a BDFD and jam the turn on any card how do I calculate the math?

My thoughts were as follows

If I open on the button SB folds and he raises to 10bbs, I call

Pot = 10+10+0.5 = 20.5

He cbets 11, I call.
Pot = 11+11+20.5 = 42.5

On the turn he cbets 22, pot is 64.5, I jam my last 79 over the turn bet
So, the odds assuming that when he calls I always lose are

79 : (64.5+79)
Or about 55%

For this example lets say I flopped an OESD and turned a backdoor flushdraw.
So roughly 25% equity on the turn.

This is probably wrong, but do I simply take the 25% of what I "own" in equity of the pot from what I am risking?

ie .25 x 143.5 = 35.88
79-35.88 = 43.12

So, finally…
Real equity adjusted odds are

43.12 : (64.5+79)
Or about 30%

Well, if we are looking at the situation starting when villain 3bets (so when we are deciding if we should call the 3bet or not) then we would be risking 97bb's (7 pre assuming 3bb open + 11 on flop + 79 on turn) to win 46.5bb's. (your 3 pre + his 10 pre + 11 on flop + 22 on turn)

If we are getting 46.5 - 97 (or 0.48 - 1) on our bluff, then villain must fold ~67.6% for us to breakeven.


Since you can't know if you are going to flop a straight draw or not, you can't really look at that preflop decision point. I'll just look at the turn decision point and hopefully that will be helpful. On the turn, after villain has bet, the pot is 64.5bb's. We are risking 79bb's to try to win the pot, however, now when called we will win 121.5bb's 25% of the time (64.5 in pot + 57 villain calls) Now, when villain calls our EV is (.25)(121.5) - (.75)(79) = -28.88bb's


So when villain folds we win 64.5bb's, and when he calls we lose 28.9bb's on avg. So we are effectively getting 64.5 - 28.9 or 2.23 - 1 on our bluff on the turn. So villain must fold 31% for us to breakeven.