Also how much will I have in 4 years if I go with a bank with average interest rate

Where are you located ?

Where are you located ?

England

Well in that case, really depends on where this sum comes from and how it's going to be deposited.
You won't lose anything on deposit, although it would make sense to use at least 2 accounts to hedge any potential issues.
As for interest after 4 years, well base rate is currently 0.5%, so you won't get much back in interest.

I'm a new saver who hasn't got a clue about money or banking I have saved some money but really don't know the best way to save it if I put it in a bank will I lose any to tax any help would be appreciated I really don't know what to do

Go have a chat with your current bank as they will advise you.

Thanks

You won't lose any of your savings to tax. But some part of your interest may be subject to taxation.