The pot odds show the relationship between the possible amount to be won and the amount you need to pay. The amount you can win in this case is the money that is already in the pot.
The implied odds also include within the possible winnings, how much you can win from the following streets. This concept allows you to call with incorrect pot odds on one street if it can be offset by accordingly high implied odds. You assume that you can win the required money on later streets.
What amount do you still need to win?
In a lot of cases, you will face a bet on the flop that you can’t call with a draw according to pot odds. This doesn’t necessarily mean that you have to give up this hand. It depends on how much you can win if you hit your draw.
You have a flush draw on the flop and your opponent bets pot size. Since the pot odds are 2:1 you can’t call profitably with a flush draw. For a profitable call you would need pot odds of 4:1.
Now the implied odds come into play. You assume that you will win more money if you hit your hand on the turn. But how much would that at least have to be?
For this, have a look at when you could call correctly on the flop:
There is $15 in the pot and your opponent bets $5. You therefore get odds of 4:1.
In this case, you get the required odds. Compared to the previous example there is $10 more in the pot. This $10 is the exact amount you would have to win on the turn and/or river.
In the first example you are getting odds of 2:1 instead of 4:1. You are therefore missing two sets of $5 which obviously equates to the required $10.
Here your opponent uses a bet of 1/2 pot size. You are getting pot odds of 3:1. To get the required pot odds of 4:1, you are missing $5.
Can you still win this amount?
You now know how much you need to win to make a profitable call. To decide whether you can actually win this amount in practice, you have to take into account the following factors:
The hand strength of your opponent: when your draw hits, he still has to be willing to stay in the hand and pay into the pot.
Special attributes of your opponent: what player type is he? A calling station for example will often take every made hand to the showdown, a maniac might barrel all three streets no matter how the board develops. In both cases you can give yourself high implied odds
How obvious is your hand? A finished flush is quite obvious for your opponent. Same goes for an OESD.