What Is a Strike Price? How Option Strikes Work
Reviewed by Leon Moyer - Published October 9, 2026 - Last reviewed October 9, 2026
In this lesson
Define the strike price, read a list of strikes, and compare how a lower or higher strike changes an option's cost and break-even.
The strike price is the fixed price at which an option's buyer can buy the underlying shares (with a call) or sell them (with a put). It is set when the contract is listed and stays the same for the life of the option, however far the stock price moves.
What Is an Option? introduced the four contract parts. Here we focus on the strike: how it affects an option's premium and payoff.
What is a strike price in stock options?
Take the XYZ 50 call. The "50" is the strike. It means the owner of the call has the right to buy 100 shares of XYZ at $50 each, whatever XYZ trades at in the market. For the XYZ 50 put, the same number means the right to sell 100 shares at $50 each.
The strike is also called the exercise price, because it is the price that applies if the option is exercised.
Two points about the strike are worth fixing in your mind early:
- The strike is not the price of the option. It is the price of the shares if the option is used. The option itself has a separate price, the premium, covered in What Is an Option Premium?
- The strike sets the cash that changes hands on exercise. Exercising one XYZ 50 call means paying $50 x 100 = $5,000 for the shares. Exercising one XYZ 50 put means receiving $5,000 for delivering them. In one sentence: cash on exercise = strike price x 100 x number of contracts.
How are strike prices listed?
You pick a strike from a menu. The options exchanges list a set of strikes for each expiration date, spaced at regular steps above and below the current stock price. When the stock moves far enough that the listed strikes no longer surround it, the exchanges add new ones.
The step between strikes is called the strike interval. It depends mostly on the stock's price and how actively its options trade. Under Cboe's general rule, strikes are $2.50 apart from $5 to $25, $5 apart from $25 to $200, and $10 apart above $200; the OIC notes $0.50 or $1 increments too.
Cboe's specifications list the standard intervals; the chain shows what is actually listed.
Here is what strikes near the stock price might look like for XYZ at $50, if it lists $2.50 strikes:
On a broker's screen these strikes appear as rows in the options chain, with calls on one side and puts on the other. How to Read an Options Chain, in the next module, walks through reading a full chain.
How does the strike price affect an option's cost?
For a call, a lower strike is a more valuable right: the right to buy at $45 beats the right to buy at $50. So, with everything else the same, lower-strike calls cost more. Puts run the other way: the right to sell at $55 is worth more than the right to sell at $50, so higher-strike puts cost more.
The price difference is not just a matter of cost. It changes where the trade breaks even, and how likely it is to pay off at all.
Worked example
Three XYZ calls, one stock price
New setup for this module: XYZ at $50, calls expiring in 30 days. The premiums below are the model prices the free profit calculator shows at its default inputs (30% implied volatility, 4.5% interest rate). Assume you fill at them; figures exclude fees and any stock-position risk after exercise:
Each break-even is the strike plus the premium per share, the long call rule from Call Options Explained. Here is what each call is worth, net of its premium, at three prices at expiration:
- The 45 call puts the most money at risk, $536, but it profits from almost any rise: XYZ needs to finish above $50.36, a gain of just 0.7%. At $48 it still keeps $300 of its value and loses $236.
- The 50 call sits in between: $181 at risk and a break-even 3.6% above today's price.
- The 55 call costs only $33, but XYZ must rise 10.7% in 30 days just to break even. At $52 the stock has risen 4%, and the call still expires worthless.
Illustrative and hypothetical. The ticker and prices are invented for teaching, and the figures exclude commissions, fees, margin interest and taxes, which reduce real results. Past or hypothetical outcomes do not indicate future results.
Same stock, three strikes
45 call
Premium: $536
Break-even: $50.36
50 call
Premium: $181
Break-even: $51.81
55 call
Premium: $33
Break-even: $55.33
Gray line: zero, where the position breaks even. Dashed line: strike. Each sketch shows profit or loss at expiration as the stock price rises from left to right.
For comparable calls, a higher strike generally lowers the premium but requires a larger rise to break even. A cheap call is not necessarily a bargain.
Cheaper strikes need bigger moves
Premium per contract
Rise from $50 needed to break even at expiration
How does the strike change the odds of a payoff?
No strike is right for every trade. The strike decides how far the stock must move before the option pays, and the useful question is: how far do you expect the stock to move, and by when?
Use the three calls to compare the premium at risk and break-even at expiration on the same basis. Also compare their bid-ask spreads: the quoted premium is not always the price at which you can fill or close a trade.
- If you expect a modest move, a strike near the stock price, or one the stock is already past, needs less of a move to pay off, at a higher cost.
- If you expect a large move, a strike further out costs less and can gain more in percentage terms if the move is large enough. It also expires worthless more often.
- Whatever you choose, decide in advance how much of the premium you can afford to lose, because a bought option can lose all of it.
The three positions a strike can take relative to the stock price have names: in the money, at the money and out of the money. In the Money vs Out of the Money explains them, and What Is Delta in Options? shows delta, a price-sensitivity measure sometimes used as a rough probability proxy, not a guarantee. How to Choose a Strike Price and Expiration from the Chain, in the next module, walks through the choice itself on a full chain.
Can the strike price of an option change?
Not because the market moves. Only a formal adjustment by The Options Clearing Corporation (OCC) after a corporate action, such as a split, merger or special dividend, changes it. The Contract Multiplier and Adjusted Options covers how.
Check your understanding
You own one XYZ 60 put. What does the 60 mean, and how much cash would you receive if you exercised it?
Show answer
The 60 is the strike: the right to sell 100 shares of XYZ at $60 each. Exercising it means delivering 100 shares and receiving $60 x 100 = $6,000.
XYZ trades at $50. With the same expiration, which usually costs more, the 45 call or the 55 call, and why?
Show answer
The 45 call. The right to buy at $45 is more valuable than the right to buy at $55 when the stock is at $50, so its premium is higher.
A 55 call costs $0.33. What is its break-even price at expiration?
Show answer
$55.33. The break-even for a long call is the strike plus the premium per share: $55 + $0.33.
Key takeaways
- The strike price, also called the exercise price, is the fixed price at which an option's shares change hands if it is exercised.
- Exchanges list strikes at regular intervals around the stock price, and add new ones as the stock moves.
- Lower-strike calls and higher-strike puts cost more, because they are more valuable rights.
- A cheaper strike needs a bigger move to break even and expires worthless more often.
- A strike never changes with the market; only an OCC adjustment after a corporate action changes it.
Common questions
Is the strike price the same as the exercise price?
Yes. The strike price and the exercise price are two names for the same thing: the price per share at which the underlying changes hands if the option is exercised.
Can the strike price of an option change?
Not because the stock moves. A strike is fixed for the life of the contract. The only exception is a formal adjustment by the OCC after a corporate action such as a stock split, merger or special dividend.
What is the difference between the strike price and the stock price?
The stock price is what the shares trade for in the market right now, and it changes all day. The strike price is fixed in the option contract: it is the price per share at which the shares change hands if the option is exercised. Comparing the two tells you whether an option is in, at or out of the money.
How far apart are option strike prices?
It depends on the stock. The exchanges list strikes at set intervals, which are narrower on lower-priced and heavily traded stocks (for example $2.50) and wider on higher-priced ones (for example $5 or $10). The chain shows the strikes actually listed for each expiration.