Setting a range that ends where data ends?

I was curious about whether, where I make computations in my macro, there was a way to set the range so it included only the cells with data. The amount of rows would be changing every time that I had to run the macro, so simply defining the range as a1:a347 or something similiar wouldn't work, and things like a:a take a long time to run.


(As of now, I have all of my formulas set for "Autofill" from row 1 to row 500 of whatever column it is needed in, however having it fill to the relevant row would be preferred)