Valuation on the estimated potential of a company? EPS, PE, etc?

Sorry if this is a newbie question, I am a newb at this and just trying to understand it all...

How do you calculate the future earnings that would be needed to justify the value of a particular stock? For example Canopy Growth has held steady around $50/share. Many are saying it is overvalued, which is true based on past/current earnings but not necessarily on future earnings after Canadian cannabis legalization. How much earnings would they need over the next few years to justify this stock price?

Is there a simple formula such as (outstanding stocks x price per share divided by estimated earnings)...or something similar?

I am not asking if CGC is a good stock to buy, but would like to know what methods people use for valuing a stock.

Thank you!

Edit: (brevity and clarity)

Submitted September 25, 2018 at 04:28PM by dunkers0811 https://ift.tt/2N3XVj8