Simple definition
The strike price is the set price at which an option lets you buy or sell the underlying investment. For a call it's the price you can buy at; for a put it's the price you can sell at. Think of it as the pre-agreed price tag written into the contract, fixed until the option expires.
Why it matters
The strike price decides whether an option is worth using. A call only pays off if the price rises above the strike; a put only if it falls below. The gap between the strike and the actual market price, along with the time left, drives an option's value — and whether it expires worthless.
Real-life example
Say you hold a call with a $50 strike price. If the stock trades at $55 before expiration, using the option to buy at $50 has value. If it never tops $50, the option is likely to expire worthless. These are rounded, made-up numbers to show the idea, not a real quote.
Common mistakes
- Thinking any option with a set strike is a sure thing, when the price may never reach it.
- Ignoring how far the market price sits from the strike, which drives whether the option pays off.
- Forgetting the option can expire worthless if the price never crosses the strike in time.
- Confusing the strike price with the premium, the separate fee you pay to hold the option.
Pro tips
- Before trading options, understand how the strike and market price together decide an option's value.
- Remember a strike far from today's price is cheaper but less likely to ever pay off.
- Weigh the strike against the time left, since both must line up for an option to work.
- Recognize that most long-term investors build wealth without ever choosing a strike price.
Related Money Dictionary terms
- OptionsContracts that give you the right, but not the obligation, to buy or sell an investment at a set price by a deadline.
- Call OptionA contract giving you the right to buy an investment at a set price before it expires.
- Put OptionA contract giving you the right to sell an investment at a set price before it expires.
- Expiration DateThe deadline by which an option contract must be used or it becomes worthless.
- LeverageUsing borrowed money to increase the size of an investment, raising both potential returns and potential losses.
- StockA share of ownership in a company that you can buy and sell, giving you a small stake in its profits and growth.
Frequently asked questions
How does the strike price affect whether an option pays off?
An option only has real value when the market price moves past the strike in your favor. A call pays off when the price rises above the strike; a put when it falls below. If the market price never crosses the strike before expiration, the option typically expires worthless and the premium is lost.
Is the strike price the same as the option's cost?
No. The strike price is the fixed price at which you could buy or sell the underlying investment. The premium is the separate fee you pay just to hold the option. Two different numbers: one sets the deal inside the contract, the other is what you pay upfront for the right to it.
Can I choose the strike price when buying an option?
Options are usually offered at a range of preset strike prices, so you pick from what's listed rather than naming any number you want. Strikes closer to the current market price cost more; strikes farther away cost less but are less likely to pay off. This is advanced ground most investors can skip.
Knowing what Strike Price means is knowledge — the first half. A brick gets placed when you act on it: Before trading options, read investor.gov's explainer on how strike prices work and paper-trade a few examples first..
Sources & references
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Plain-English education — not personalized legal, tax, or investment advice.