I am not an expert or genius with calculation matters, so all I can do is to suggest you to check out this https://cryptolinks.com/bitcoin-calculator, as I feel this is something that should HELP you in a really good way.

Although, there are many other ways as well for the calculation, but it’s sensible only that we don’t try to complicate something like this one, instead go for a route that’s simple, straightforward and pretty much easy! I prefer this only for such calculation.