Put Options Explained - The Right to Sell
Reviewed by Leon Moyer - Published September 29, 2026 - Last reviewed October 9, 2026
In this lesson
Calculate the cost, break-even price and profit or loss at expiration of a long put, and explain how a put can protect shares you own.
A put option gives its buyer the right, but not the obligation, to sell 100 shares of a stock at the strike price, on or before the expiration date.
If a call is the right to buy, a put is its mirror image. Put buyers generally benefit when the stock falls, and puts have a second use that matters to many investors: they can act as insurance on shares you already own. At expiration, a long put breaks even at the strike minus the premium, loses at most the premium, and makes at most the strike minus the premium, if the stock falls to zero.
How do put options work?
All else being equal, a put is worth more when the stock is lower, because the right to sell at a fixed price becomes more valuable as the market price drops. As with calls, time passing and changes in implied volatility also move a put's price before expiration, and they can outweigh a favorable move in the stock (see the Options Industry Council's option price behavior guide).
If you own the right to sell XYZ at $50:
- When XYZ trades at $55, your right is not useful today. Why sell at $50 when the market will pay $55?
- When XYZ trades at $40, your right is very useful. You can sell at $50 something the market values at only $40.
A put's intrinsic value is the strike price minus the stock price, or zero if the stock is at or above the strike. At expiration, intrinsic value is all a put is worth. Before expiration, it also carries time value, just like a call. A put is in the money when the stock is below the strike and out of the money when it is above; In the Money vs Out of the Money covers these terms in depth.
What are a long put's break-even, maximum loss and maximum profit?
- Maximum loss = the premium you paid. If the stock finishes at or above the strike, the put expires worthless.
- Break-even price = strike price - premium per share. The stock has to fall far enough below the strike to pay back the premium.
- Maximum profit = strike price - premium, per share. A stock cannot fall below zero, so a put's profit has a ceiling. It is large, but it is not unlimited the way a call's is.
Worked example
Put option example: buying one XYZ 50 put
XYZ trades at $52. You buy one XYZ 50 put that expires in 45 days for a premium of $1.50 per share.
- Cost: $1.50 x 100 = $150.
- Break-even at expiration: $50 strike - $1.50 premium = $48.50.
- Maximum loss: $150, if XYZ is at or above $50 at expiration.
- Maximum profit: ($50 - $1.50) x 100 = $4,850, reached only if XYZ falls to $0.
The shape is a mirror of the long call: a flat loss above the strike, then $100 of profit for every $1 the stock falls below the break-even.
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.
Long XYZ 50 put bought for $1.50, at expiration
Hover or tap the chart, or focus it and use the arrow keys, to read any price.
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Why buy a put option?
To profit from a decline: a put vs short selling
A trader who expects XYZ to fall can buy a put instead of short selling the stock. Short selling means borrowing shares and selling them, hoping to buy them back cheaper later. It has a serious drawback: if the stock rises instead, the losses have no ceiling.
A long put expresses the same bearish view with a known, limited risk: the premium. The trade-off is the same as with calls. The put has a deadline, and the stock has to fall far enough, soon enough, to cover what you paid.
To protect shares you own: what is a protective put?
This is where puts behave like insurance. Buying a put on a stock you hold is called a protective put, and it sets a floor under the value of your shares until the put expires.
100 shares at $52, with and without a 50 put
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Worked example
Insuring 100 shares with a protective put
You own 100 shares of XYZ, currently at $52. You are worried about an earnings announcement next month but do not want to sell. You buy one XYZ 50 put for $1.50 ($150).
- If XYZ drops to $38: your shares have lost $1,400 in value ($52 to $38). But your put is worth $12 per share ($50 - $38), or $1,200. Net of the $150 premium, your total loss is $1,400 - $1,200 + $150 = $350, instead of $1,400.
- If XYZ rises to $60: your shares gained $800. The put expires worthless and you are out the $150 premium, so you keep $650.
Like any insurance, the protection costs money whether or not you end up needing it. The floor here is $50 per share, and the cost of that floor is the premium plus the $2 per share between the current price and the strike. In general, the most a protective put can lose = (share price when you buy the put - strike + premium) x 100, measured from the shares' value on that day.
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.
What can you do with a put before it expires?
A put buyer has the same three choices as a call buyer:
- Sell the put to close the position and keep or lose the change in premium. This is the most common exit.
- Exercise the put and sell 100 shares at the strike price. If you do not own the shares, exercising creates a short stock position, which most beginners should avoid.
- Hold to expiration. An in-the-money put is generally exercised automatically at expiration unless you instruct your broker otherwise. If you do not own the shares, that leaves you short 100 shares. What Happens When Options Expire? explains how to handle expiration safely.
What does a long put payoff diagram look like?
A long put's payoff diagram is flat at the maximum loss (the premium) at any stock price at or above the strike. Below the strike it rises $100 for every $1 the stock falls, crossing zero at the break-even (strike - premium). It is the long call's shape flipped left to right. Add a single long put in the free OptionsPro profit calculator and move the stock price to see it.
Check your understanding
You buy a 40 strike put for $2.00. What is your break-even price at expiration?
Show answer
$38.00. Break-even for a long put is the strike minus the premium per share: $40 - $2.00.
Why is a long put's maximum profit limited while a long call's is not?
Show answer
A stock price cannot fall below zero, so the most a put can be worth is its strike price. A stock has no upper limit, so a call's value has no fixed ceiling.
What is a protective put?
Show answer
Buying a put on shares you already own. It sets a floor under the value of those shares until the put expires, at the cost of the premium.
Key takeaways
- A put is the right to sell 100 shares at the strike price. All else equal it gains value as the stock falls, but before expiration time decay and falling implied volatility can outweigh that move.
- Long put break-even at expiration is the strike minus the premium per share.
- The most a put buyer can lose on the option is the premium (a short stock position from exercise carries separate risk); the most they can make is the strike minus the premium, reached if the stock goes to zero.
- Puts can express a bearish view with limited risk, or protect shares you own like an insurance policy.
Common questions
What does it mean to buy a put option?
It means paying a premium for the right to sell 100 shares at the strike price on or before expiration. Traders buy puts to profit if a stock falls, or to protect shares they already own.
Can you lose more than you pay for a put option?
Not on the option itself: the most a put buyer can lose is the premium paid, plus commissions, unlike short selling a stock, where losses have no fixed limit. If an in-the-money put is exercised and you do not own the shares, the resulting short stock position carries its own risk.
Do I need to own the stock to buy a put option?
No. You can buy a put to profit from a decline without owning shares. If it is in the money at expiration and you do not own the shares, it is generally exercised automatically and leaves you short 100 shares per contract, so most traders sell the put before then.
When would you use a protective put?
When you want to keep shares through a risky stretch, such as an earnings report, but limit how much you could lose. The put sets a floor at its strike price until it expires, in exchange for the premium.