The Chicago Manual of Style (17th ed.), 6.52, says (I cannot provide a link as it's behind a paywall for the online version):
The adverbs too and either used in the sense of “also” generally need not be preceded by a comma.
I had my cake and ate it too.
Anders likes Beethoven; his sister does too.
The airport lacked charging stations; there were no comfortable chairs either.
When too comes in the middle of the sentence or clause, however, a comma aids comprehension.
She, too, decided against the early showing.
So, if too is at the end of a sentence, as in your question, then Chicago would likely not use a comma; if it's in the middle of a sentence, then it probably would.
This is more direct than what is relayed by the FAQ entry provided in the other answer. But if you look at the full text of that entry, you'll see there's more to it and that it gives similar examples:
A comma can do some work in making the meaning of a sentence clear, but to claim two different meanings for I like apples and bananas too with and without a comma before too puts too much pressure on the comma. Out of context, neither version would be perfectly clear. To make the different meanings more apparent, short of additional context, you’d have to be more explicit:
I, too, like apples and bananas.
I like not only apples but bananas too.