You buy a call option on AAPL with a strike of K=220. At maturity of the call, the price of AAPL is $206.00. What is the payoff per option" from the call option? Do not multiply by 100 for a lot of options. A buyer of call has you the right, but not the obligation to buy the underlying at the strike price, instead of buying it at the market price. If the price on the market is higher than the strike, than the buyer of the call can use the option to pay a lower price. We call this difference in price the "payoff of the option". If the price on the market is lower, then the option is worthless and the payoff of the option is simply zero