Pot Odds

You here it all the time in the freerolls... "Well, I had pot odds so I had to call", but I do not think most people understand this...

Here is an excerpt from Mike Caro's article, Todays Word Is... Odds, found here:

Question 139: You say the importance of poker odds is overestimated. But
aren’t you the guy who’s spent a good share of his life calculating those odds?

I’m that guy. In the 1970s, I calculated lots of poker odds, and I’ve been doing
so ever since. When Doyle Brunson’s Super/System—A Course in Power Poker was
published in 1978, I contributed 50 statistical table covering various forms of
poker. Up until then, no truly comprehensive set of poker odds was available—at
least none that I’ve ever seen. Poker books in those days were basically
homespun wisdom, and the math included was frequently wrong and not very
encompassing.

Hopefully, I corrected that shortcoming. But I did something more than
that—something worse. I became obsessed with poker odds and with calculating new
ones. You don’t need to share this obsession to play excellent poker. In fact,
you don’t need to calculate odds at all, because mine and other sets of
excellent statistics are easy to come by. You can even memorize them, if you
want. But you don’t need to. You’d be surprised how small your extra edge is
after you’ve memorized the exact odds.

What mostly sets great poker players apart from ordinary ones is an
understanding of opponents and a good feel for what decisions to make at the
moment. Sure, you need to know approximately what your chances are—and the
closer you come to the exact number, the better you’ll fare. But the difference
between knowing approximately and knowing exactly is small in terms of profit.

Question 140: Are there any poker odds that are important enough to memorize?

Yes. Those are usually ones that come up repeatedly in your game. In hold ’em,
you’ll average a starting pair once in 17 hands. If you begin with a pair, on
average you’ll flop at least one more of that rank twice in 17 hands. A pair of
aces shows up once in 221 deals, on average. That gives you good perspective and
teaches you patience.

Those are the kind of statistics that it’s good to know. But even if you don’t,
you’ll still probably make money, as long as you have a good understanding of
situational and psychological poker, seek out weaker opponents, and play a
disciplined game.

Question 141: How do you use pot odds?

You count the chips in the pot and measure them against what it will cost you to
call or bet. Then you equate that to the chances of your hand winning. For
instance, if there’s one card to come in hold’em and you’re trying for an
unbeatable flush, you’ll figure that there are six cards you know about (two in
your hand and four on the board). Of these, four cards of your suit are
accounted for. Among the 46 unknown cards are nine remaining members of your
suit. Divide 46 by 9 and you see that you’ll connect once in 5.1 times, so the
odds are a bit more than 4-to-1 against you. If the pot is more than four times
as large as your bet, you’re getting an overlay. If it’s less, you aren’t.
Unfortunately, it isn’t quite that simple.

Question 142: Are pot odds always a good measurement when deciding what to
do?

No. I just said it wasn’t quite that simple. You need to factor in the amount of
additional money you might win or lose from that point on. Many experts call
this “implied odds”—and I think David Sklansky was the first to coin that term.
If not, I’m giving him credit anyway, because he’s contributed vastly to poker
theory and understanding.