I am aware of the Rental Property Calculator. Does Bigger Pockets have a calculator specifically for short-term vacation rentals? Some things I can think of that the Rental Property Calculator doesn't have would be on-season & off-season rates & vacancies, cleaning fees, linen and toiletry expenses, etc.
You won't be able to put in off-season rates however, I haven't seen one that does that. You'll have to estimate your average nightly rent over the year.
BP does indeed have one. it disappeared for a while but now it is back. It is under the tools section.