Quote Originally Posted by spot
Jack- thats where your math error is coming into play. 5 dollar pot- I bet 10 dollars. That means that you have to bet 10 dollars to win 15 dollars. You can't count the 10 you put in as part of your winnings becuase you are giving that money up voluntarily.
This seems to be quite a common misunderstanding.

Quote from the strategy guide:
"The pot is current at $8.00, and Player1 bets $2.00. (...) I have to call a $2.00 bet to win what will be a $12.00 pot. Since my bet is only about 17% of the pot (...) Now let's say Player1 bets $12 instead of $2. I would have to call $12 to win what will be a $32 pot. My bet is 37.5% of the pot"

See? It should be more easily understable if I put it this way:

In the above example, betting 12$ for a $8+$12 pot is 60%. This would mean I need better than 60% odds to win to make this profitable according to pot odds theory. Now, obviously anything above 50% is bogus.. if my chances of winning are >50% then EVERY bet, no matter how big, is in my advantage!

So using the correct math of calculating your bet towards the pot which would include your bet (so $12 for a $8+$12 pot is 12/32 or 37.5%, not 12/20 or 60%!) then you can never get more than 50% here. This should be intuitively obvious. Having more than 50% to win is always favorable, so calculating a pot-addage over 50% is a clear indication of an error.

Example: Pot is 10$. opp goes all-in for $1000. If we don't include our own input in the calculation, we'd arrive at 99%. This would mean we'd even have to fold AA vs 27 unsuited! Because here we "only" have 88.8% chance to win, which is less than 99% we calculated.
(to be complete: the correct odds here are 1000/2010=49.75%)

Ofcourse this is preflop. If this doesn't convince you, postflop:
Example 2:
My hand: AA
Opp hand: 26 hearts
Flop: As Ts 9h

pot is $10. Opp raises $1000. I have a 95.6% to win.. my opp can only win if he hits his flush on turn+river, which would happen 4.4% of the time. But if we go 99% of pot-addage, I'd have to fold this, since I have "bad pot odds" as 95.6%<99%. This should be obviously bogus

Hope this clears things up.