It depends on, what you mean by "calculating odds". Such a term is often used when deciding to call with a draw, but the decision is really more complicated than just determining your
pot odds. Its also about the quality of your draw, your implied odds and other factors like your position, and how many people are still in the hand.
Lets say you are holding Js9s on QhTh2s-Ad and face a turn bet. You still have 8 outs to make a straight, but Kh or 8h can potentially set you up to lose a big pot to a flush. Any K will also create a 1-liner to a straight, where you are chopping with another J, and its difficult to get much value from worse. And finally someone could already have a straight with KJ, in which case you are drawing dead.
So this is a very bad draw, and realising that is more important than calculating your exact pot odds. Maybe you can still call a very small bet, but if someone make a substantial bet, you should just get out, especially if its a multiway pot. You especially dont want to call, if other players are still left to act behind you, who could potentially put in a raise.