How to Calculate Cash-Secured Put Return and Breakeven
Selling a cash-secured put means you’re setting aside enough cash to buy 100 shares at a strike price if the option gets assigned, in exchange for collecting a premium up front. The strategy is popular for generating income or for getting into a stock at a discount, but comparing one put to another requires more than just looking at the premium dollar amount. This guide covers the core formulas, including the one most traders skip: annualizing the return so you can compare puts with different expirations on equal footing.
For the strategy mechanics, see selling naked puts or the cash-secured put 101 guide. To skip the manual math, the options profit calculator can compute all of this for you instantly.
The Core Formulas
Capital Required
Capital required = strike price × 100 × number of contracts
This is the cash you must set aside to secure the put — enough to buy the shares at the strike price if you’re assigned. It’s the same regardless of how much premium you collect or how far out the expiration is.
Max Profit
Max profit = premium received
The most you can make on a cash-secured put is the premium you collected up front. If the stock stays above the strike through expiration, the put expires worthless and you keep the entire premium — that’s the ceiling, no matter how far the stock rises.
Breakeven
Breakeven = strike − premium
If the stock is assigned, you effectively buy the shares at the strike price, but the premium you collected offsets part of that cost. You don’t start losing money until the stock (and your effective purchase price) falls below strike minus premium.
Return on Capital
Return on capital = premium / strike
This tells you the percentage yield you’re earning on the cash you’ve tied up to secure the put, based purely on the premium collected.
Annualized Return
Annualized return = return on capital × (365 / days to expiration)
This is the formula traders most often skip, and it’s the one that matters most for comparing opportunities. A put expiring in 7 days and a put expiring in 45 days can have similar dollar premiums, but the 7-day put is generating that return in a fraction of the time. Annualizing converts both into a comparable “per year” rate, the same way you’d compare a savings account APY to a bond yield, so you can judge which trade is actually more attractive on a time-adjusted basis. Without annualizing, you’d be comparing two returns that aren’t measuring the same thing.
Effective Cost Basis If Assigned
Effective cost basis if assigned = strike − premium
Note this is identical to the breakeven formula above. If you do get assigned shares, your true cost per share isn’t the strike price — it’s the strike minus whatever premium you already banked.
Worked Example: Comparing a 7-Day Put and a 45-Day Put
Suppose a stock is trading at $100, and both a 7-day put and a 45-day put are available at the same $95 strike, with premiums that happen to be fairly close in dollar terms:
- 7-day put: premium = $0.50
- 45-day put: premium = $1.50
Capital Required (both puts)
Capital required = $95 × 100 × 1 contract = $9,500
This is identical for both, since it only depends on the strike price.
Breakeven
- 7-day put: $95 − $0.50 = $94.50
- 45-day put: $95 − $1.50 = $93.50
Return on Capital
- 7-day put: $0.50 / $95 = 0.005263 = 0.53%
- 45-day put: $1.50 / $95 = 0.015789 = 1.58%
At first glance, the 45-day put looks like the better deal — roughly three times the return on capital.
Annualized Return
- 7-day put: 0.53% × (365 / 7) = 0.53% × 52.14 = 27.4%
- 45-day put: 1.58% × (365 / 45) = 1.58% × 8.11 = 12.8%
Once you annualize, the picture flips. The 7-day put is generating a much higher annualized rate of return — more than double the 45-day put — because it earns a smaller absolute premium in a much shorter window, and that shorter window compounds (in theory) more frequently over a year.
| Metric | 7-Day Put | 45-Day Put |
|---|---|---|
| Strike | $95 | $95 |
| Premium | $0.50 | $1.50 |
| Capital required | $9,500 | $9,500 |
| Breakeven | $94.50 | $93.50 |
| Return on capital | 0.53% | 1.58% |
| Annualized return | 27.4% | 12.8% |
Why This Matters in Practice
Annualized return isn’t a guarantee — it assumes you could repeat a similar trade back-to-back for a full year, which depends on premiums, strikes, and market conditions staying roughly consistent, and it ignores the extra trading costs and effort involved in rolling a position every week. Shorter-dated puts also carry different gamma and assignment risk profiles than longer-dated ones. But as a like-for-like comparison tool, annualizing return on capital is the only way to fairly judge whether a 7-day put or a 45-day put is the more efficient use of your cash.
Frequently Asked Questions
How do you calculate the return on a cash-secured put? Divide the premium received by the strike price: return on capital = premium / strike. To compare puts with different expirations, annualize that figure by multiplying by (365 / days to expiration).
Why does annualizing return matter for cash-secured puts? Because two puts can have very different premiums but very different timeframes. A put with a smaller premium but a much shorter expiration can have a higher annualized return than a put with a larger premium over a longer period. Annualizing puts both trades on the same time-adjusted scale.
What is the breakeven on a cash-secured put? Breakeven equals the strike price minus the premium received. If the stock falls below this level and you’re assigned, your position is underwater relative to the current market price.
What’s the maximum I can lose on a cash-secured put? Your maximum loss occurs if the stock falls to zero: you’d be obligated to buy shares at the strike price, offset only by the premium collected, for a max loss of (strike − premium) × 100 × contracts. In practice, a stock falling to zero is rare, but it illustrates that a cash-secured put carries substantial downside risk despite the premium cushion.