[VoraciousReader]

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We have an equity in this situation because we have a 1 in five chance of winning the pot and the bet on the turn only represents 1/12 of the pot. Its the same reason why we could pump the flush draw on the flop. Our equity in the situation hasn't decreased enough relative to the size of the pot.
On the flop we stood to win by the river about 1 in 3 times. On the turn, it's now about 1 in 5. The only difference is there's more money in the pot. If no one calls, we take it down UI. If everyone calls we still have a 1 in 5 chance of winning. Not to mention any bets we collect on the river.


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I see where the thought process came from, but you really have several concepts jumbled here, and the result is kind of a mess.

We are about 1 in 5 to hit our flush, which should give us the winning hand. Therefore, we can certainly call a turn bet. That does not mean betting it is a good idea.

You should consider the money already in the pot when you are deciding to call or deciding to bluff. (I know you're not the OP, but for the sake of simplicity, I'm going to pretend you're playing this hand.) If you had one opponent here who checked to you, you might consider a semi-bluff bet. You would be risking 1 bet to take down a pot of 11 bets. And if you get called, you still have a reasonable chance to win. So you'd think about your opponent and whether he/she would likely fold this more than 1 out of 11 times if you bet the turn. If you think that's a reasonable expectation, go ahead and bet.

But when you're deciding whether to bet for equity you are trying to decide if you are getting full value on your investment. You want to put in less than your share of the money, while your opponents put in more than their share. We are interested in money currently going into the pot.

Since you are slightly better than 1 in 3 to win on the flop, if you bet/raise and get 2 callers, you have made money. You invested 2 dollars and the callers each chipped in 2 dollars. But of the 6 dollars that just went in , you can reasonably expect to win about $2.10. Your opponents can only expect to win $3.90 of their money back.

If you get 3 callers, it gets even better, because you expect to get $2.79 back on your $2 investment. So the more callers you get, the happier you are.

On the turn, however, you're now only half as likely to make your hand. So you need twice as many callers to be ahead on your investment. Not people who saw the turn with you, but people who actually call your bet. It doesn't matter how big the pot is now. Unless they're all folding (very unlikely with 4 to the turn) you are now generally losing money when you bet this turn. You may gain a smidge of expectation if you can fold out an ace, but probably not enough to compensate for the whole bet you spend...when the alternative was seeing the river for free.

Not only are you unlikely to get value out of a bet, but you are in last position and don't have to worry about having to call a bet behind you if you check.

Disclaimer: Not a math person, so anyone who wants to check these numbers, please do so.