Drawing to X outs: (46-X) / X : 1.
This is the generic formula. If you're another draw than the ones I've listed above, and want to figure out your odds for it, you do this: Figure out your number of outs (you're on your own there), then take 46 minus this number. Divide the result by the number of outs, and voila - you have your odds. For example, if I'm drawing both to a set and to a flush, e.g. I have reason to believe my opponent has two pair, and I have AA, with four to a flush, my outs are any ace (giving me a set) plus 9 flush cards (giving me a flush), totalling 11 outs. This gives:
46 - 11 = 35.
35 / 11 = 3.2
My odds of drawing a winner are 3.2 : 1
This is from the strategy section at CardsChat.
One question from me, why is it 46, and not 47? Maybe Im being dumb?