Options Calculator

An option is a contract: it gives its owner the right — but never the obligation — to buy (a call) or sell (a put) 100 shares of a stock at a fixed strike price, any time before it expires. For that right the buyer pays a premium up front; the seller (the 'writer') collects it and takes on the matching obligation. Because the buyer can simply walk away when the option would lose money, the payoff is bent rather than straight — and plotting profit against the stock's price at expiration draws the shapes that make options click. A long call loses only the premium below the strike but profits without limit as the stock climbs past break-even: defined risk, unlimited upside. A long put mirrors it for a falling stock. The seller's diagram is the buyer's flipped upside down: a short call collects a small premium but carries unlimited loss if the stock soars, which is why a naked short call is among the most dangerous positions in finance; a short put earns the premium in exchange for a large but capped loss if the stock collapses. The second idea the simulator makes visible is that an option's price is two things added together: intrinsic value (how far it is in the money right now) plus time value (the extra you pay for the chance it moves further before expiration). Time value erodes to exactly zero as expiration approaches — so an option is a wasting asset, and a buyer can be right about direction yet still lose to the clock. The durable lesson: options let you shape risk precisely, but every payoff you buy is sold by someone taking the opposite shape, and the premium is the price of that asymmetry.

Free and interactive — no sign-up, nothing to install. Read the full lesson for the plain-language explanation.