Can someone please explain these odds?

[silversun87]

Hello,

I lost a hand playing today and I wanted to check in the odds calculator if I made a good call.

The hand went somehow like this:
I don't remember my starting position just that 6 people limped in the pot including me with K10o. I flopped a straight JQ9. I was third to act after two checks and I bet pot size. Some guy went all in and the rest folded. I had nuts at the time but there were two spades in the flop which could potentially give my opponent a flush. I had about double his chips so decided to call thinking that even if he has two spades I should still be a slight favorite. He had the 87s, made the flush on the turn and won the hand.

Now for the interesting part. If you look at the attached pictures, the pots calculator gives him better odds preflop (40%) then after the flop (36%) where he had a flush draw. Is that correct? Shouldn't he get closer to 50% odds with flush draw? Or is it just because 4 spades are already in play his chances drop by so much?

 

[iwont20]

If you're all-in on the flop, your odds = your outs*4.
(13 spades - 4 spades already on the board)*4=36%

If you want to count your odds only for the next street (e.g. from flop to turn or from turn to river) the formula is your odds*2.

Read more here: https://www.cardschat.com/odds-for-dummies.php

 

[Collin Moshman]

I agree that it's counter-intuitive that picking up a flush draw lowers your equity, but it's true -- picking up a flopped flush draw against a strong made hand is a worse than average outcome when you consider that you could also flop a monster or just be a decent favorite with a flopped pair.

Iwont20 is correct on the odds calculation. (Just be careful if you have a large number of outs since the Outs * 4 calculation will over-state your equity at the flop if you have much more than 8 outs.)

 

[SharkFinn]

Preflop there are lots of ways that 87s can win the hand - flush, straight, pair etc. But since you flopped a straight, now the only way villain can win is with a flush, so even though they flopped a flush draw it's a worse situation than they were in preflop. I think the most intuitive way to think about it is that even though villain flopped well by picking up the flush draw, you flopped even better with the made straight, so naturally the odds are going to tilt in your favor.

 

[CallmeFloppy]

I think Sharkfinn hit it on the head there. A flush is now the way to win. You no longer are able to win simply by hitting a pair.

 

[silversun87]

Thank you all!
Indeed it seemed counter intuitive initially but it made total sense after I let it sink in. Sorry for the impulsive post haha