Question : How long do most people stay in Helsinki?
Answer : Of course you're not most people, but if you were, you'd stay roughly 17 days.
Question : What price range should you expect when booking from Knoxville (TYS) to Helsinki (HEL)?
Answer : Ranging anywhere from $860 to $1,860, prices for TYS to HEL do change a lot more than the majority of routes from the United States. The further out you book a route, the more likely you are to save.