Cash Secured Put Calculator
Sell a put and set aside enough cash to buy the shares at the strike price. See your premium, break-even, returns and profit or loss at every price up to expiry.
Stock
Put you're selling
Calendar days to expiry: 35
Manual settings
Left blank, it's worked out from your premium.
Has only a small effect. Leave at 4% if unsure.
Example trade shown. Replace with your own numbers.
Profit / loss by stock price
Profit / loss over time
Values before expiry are estimates using Black-Scholes and the implied volatility above. Assumes you hold to each date shown and ignores closing fees and dividends. For educational purposes only.
What is a Cash Secured Put?
A cash secured put is a way to earn income from a stock you'd be happy to own, or to buy it for less than today's price. You sell a put option and set aside enough cash to buy 100 shares at the strike price for each contract. In return you collect a premium straight away.
If the stock stays above the strike price at expiry, the put expires worthless and you keep the whole premium. If the stock finishes below the strike, you'll usually be assigned. You buy the shares at the strike price, and the premium you collected lowers your real cost.
How to use this calculator
1. Enter the stock's current price. Adding the ticker symbol is optional.
2. Enter the strike price of the put you're selling, and the premium per share you'll receive.
3. Set the expiry date, or type the number of days to expiry.
4. Enter how many contracts you're selling and any fees per contract.
The calculator updates as you type. You'll see:
- The premium you collect, the cash you need to set aside, and your break-even price.
- Your return on the cash set aside, both for this trade and annualised.
- Your chance of making a profit and your chance of being assigned.
- A chart of your profit or loss at different stock prices, today, at two dates in between, and at expiry. Hover over the chart (or tap it on a phone) to read exact values.
- A table of profit or loss by stock price and date, shown in dollars or as a percentage of the cash set aside.
You can find the premium in your broker's option chain. Use the mid-price between the bid and the ask for a realistic figure. Under "Manual settings" you can enter the implied volatility yourself, change the interest rate, or set the price range shown in the chart and table.
When is a Cash Secured Put a good choice?
- You're neutral to mildly bullish on the stock and don't expect a big fall.
- You'd be happy to own the shares at the strike price. This matters most, because assignment is a normal outcome.
- You want to buy a stock below today's price and get paid while you wait.
- Implied volatility is higher than usual. Premiums are richer, so you're paid more for the same risk.
- You're running the wheel strategy: sell puts until assigned, then sell covered calls on the shares.
When might it not suit?
- You expect the stock to fall sharply. Your losses grow much like owning the shares, cushioned only by the premium.
- You don't want to own the stock, or can't afford to tie up the cash.
- There's a big event before expiry, such as an earnings report, unless you're comfortable with a large price move.
Things to keep in mind
- Your maximum profit is the premium collected. Your maximum loss is the strike price minus the premium, if the stock went to zero.
- The break-even price is the strike minus the premium per share. Below that, you're losing money at expiry.
- You can be assigned before expiry, especially if the stock drops well below the strike. Make sure the cash is there.
- Many traders buy the put back early once they've captured most of the premium, freeing up the cash for the next trade.
This calculator gives estimates for educational purposes only. It isn't financial advice. Option prices before expiry are modelled, and real prices will differ.