The projected profit is calculated using a model called Black-Scholes, which is the industry standard for pricing options. The model takes the current stock price, the option's strike price, the time remaining, and the level of volatility the market is currently pricing in - and produces a fair value for the option at the projected stock price.
In plain terms: we ask "if the stock moves exactly as much as the market expects, what would this option be worth?" and show you that number as the projected profit. The returns shown are estimates, not guarantees.