Cash-secured put calculator
Premium, breakeven, return on collateral, and annualized return, with the actual math
A cash-secured put sells a put option and sets aside enough cash to buy the shares if you are assigned. You collect the premium up front, and you agree to buy the stock at the strike if it falls below it. Traders use it to earn income or to get paid while waiting to buy a stock lower.
Worked example, priced with the same Black-Scholes engine the calculator runs: you sell the $95 put, 30 days out, at 45% implied volatility, secured by $95 of cash per share.
If the stock stays above $95, the put expires worthless and you keep the full $2.78, a 2.92% return on the cash you set aside in 30 days. If it falls below $95 you buy the shares, but your effective cost is only $92.22 thanks to the premium. The 35.6% annualized figure assumes you repeat the trade at the same premium every cycle — not a promise.
Open the cash-secured put calculator → Loaded in Income mode with this exact trade. Change the strike or expiry and watch the return on collateral update.How to read it
The board shows the position's profit and loss versus your cash collateral at every future date and stock price, and the panel shows premium, breakeven, and both the static and annualized return. Use the implied volatility from your broker's chain for a realistic premium.
Frequently asked questions
What is a cash-secured put?
Selling one put option while holding enough cash to buy 100 shares at the strike if assigned. You collect the premium now and agree to buy the stock at the strike if it falls below it by expiry. It earns income or gets you paid to wait to buy a stock cheaper.
What is my breakeven and max profit?
Breakeven is the strike minus the premium: $95 - $2.78 = $92.22. Max profit is the premium itself, $2.78 per share, kept in full if the stock stays above the strike and the put expires worthless.
What is the return on collateral?
Premium divided by the cash you set aside (the strike, $95 here): $2.78 / $95 = 2.92% over 30 days. Annualized by multiplying by 365 over the days to expiry gives 35.6%, assuming you repeat the same trade at the same premium, which is not guaranteed.
What if the stock drops below the strike?
You are assigned and buy 100 shares at the strike. Because you collected the premium, your effective cost basis is the breakeven, $92.22, below the strike. If you did not want the shares, you can buy the put back or roll it before expiry.