From the Pot Odds essay in the HTML section of the site:

For example, let's say I am holding JT offsuit.
The flop comes A 8 9 - rainbow.
The pot is current at $8.00, and Player1 bets $2.00. Everyone else folds.

Should I make the call?

[snip]


Now back to our scenario, I have to call a $2.00 bet to win a $10.00 pot. Since my bet is only 20% of the pot, yet I have a 31.5% chance of winning, the "pot odds" justify making the call.

Now let's say Player1 bets $10 instead of $2. I would have to call $10 to win a $20 pot.
Wouldn't the pot be only $18, not $20? I think you want to say that Player 1 bets $12.