[WalkAmongUs]

3 outs on flop = 3/47 = 44:3 odds = 14.66:1 odds. You should usually only be looking at the next card to come. If you use flop to river odds, you must take into account the fact that you'll have to call a bet on the flop AND the turn.

Edited to say: If you're getting 11:1 on the flop and you use the flop to river odds, you're really only getting 13:3 effective odds, because you have to call a double size turn bet to see the river and if you use flop to river odds you HAVE to see the river.