Cash Secured Put Calculator

A cash-secured put is an options income strategy where an investor sells a put option on a stock they are willing to own, while simultaneously holding enough cash in their account to purchase those shares if the option is assigned. The seller collects an upfront premium from the buyer and, in return, accepts the obligation to buy 100 shares per contract at the chosen strike price if the stock trades below that level at expiration.

This strategy sits at the intersection of income generation and stock acquisition at a discount. Unlike purely speculative options trades, cash-secured puts are structured around a willingness to own the underlying stock. The premium income offsets the effective purchase price, giving the seller a built-in buffer against modest price declines.

Because the seller holds the full cash needed to buy the shares, the position is considered fully collateralized — there is no margin leverage and the maximum loss is the effective cost basis of the shares, not an unbounded exposure. This makes it one of the more conservative options strategies available to retail investors, often approved even in basic options trading accounts.

The strategy is popular among dividend investors, value investors, and those who regularly practice systematic put selling to lower their cost basis or generate yield on idle cash. Many traders repeat it month after month on the same ticker, rolling or accepting assignment depending on market conditions.

Understanding the precise numbers — cash required, premium income, annualized return, break-even price, and scenario outcomes — is critical before entering any position. The cash-secured put calculator on this page computes all of these values instantly from your inputs, so you can evaluate every trade before committing capital.

The calculator accepts six inputs that define your trade. Enter each value to see your premium income, return metrics, effective buy price, and a full scenario analysis — all updated in real time.

• Current Stock Price: The market price of the underlying stock right now. Used to classify the put as OTM, ATM, or ITM and to compute the discount from the current price.
• Strike Price: The price at which you agree to buy the shares if assigned. Lower strikes mean lower assignment probability but also lower premiums.
• Premium Received (per share): The option premium quoted in dollars per share. Each contract covers 100 shares, so total income equals premium × 100 × contracts.
• Number of Contracts: How many put contracts you are selling. One contract = 100 shares of obligation and cash requirement.
• Days to Expiration: How many calendar days remain until the option expires. This is used to annualize the return on cash.
• Target Buy Price (optional): If you have a desired entry price for the stock, enter it here to see how much you save by using the cash-secured put strategy versus buying at that target price outright.

Once all fields are filled, the calculator displays your total premium income, return on cash, annualized return, effective buy price, discount from current price, break-even, maximum loss, and a five-scenario expiration table ranging from a 30% stock drop to a 10% stock rise.

The most important output is the effective buy price — the net cost per share you pay if the option is assigned. This equals the strike price minus the premium per share. If the stock closes below the strike at expiration, shares are put to you at the strike, but your real acquisition cost is reduced by the premium you already collected. A lower effective buy price means a better deal if you ultimately own the shares.

The return on cash measures the premium income as a percentage of the capital you set aside to secure the position. This is the most direct profitability metric for the trade. The annualized return scales this figure to a yearly rate so you can compare trades of different durations on equal footing. A 30-day trade that earns 2% return on cash annualizes to roughly 24%, while the same dollar return from a 60-day trade annualizes to only 12%.

The scenario table shows profit or loss at five different stock prices at expiration: a 30% drop from strike, a 15% drop, exactly at the strike, at the current stock price, and 10% above the current price. Scenarios where the stock closes above the strike result in the option expiring worthless — you keep the full premium. Scenarios below the strike result in assignment, and your profit is the total premium minus the loss on the stock position (strike minus expiration price, times shares). This table makes it immediately clear how severe a stock decline needs to be before your trade posts a loss.

The maximum loss is reached if the stock falls to zero — a theoretical worst case. In practice, almost no stock reaches zero without warning, giving you time to close the position. The strategy assessment label — Conservative (Deep OTM), Moderate (Slightly OTM), Neutral (Near ATM), or Aggressive (ITM) — gives a quick read of assignment probability and risk level.

One of the most appealing features of the cash-secured put is that it has two potentially profitable outcomes, not one.

Expires worthless: If the stock closes above the strike price at expiration, the put option expires with no value. The buyer has no incentive to exercise it. You keep the entire premium you collected, your cash is returned, and you are free to sell another put in the next cycle. This is the highest-return outcome on a cash basis — you earn income without buying a single share.

Assigned: If the stock closes below the strike price, the option is exercised and you are assigned 100 shares per contract at the strike price. Your cost is then reduced by the premium already received, giving you an effective purchase price below the strike. If this effective price is still below your assessment of fair value, assignment is a positive event — you acquired the stock at a discount. Many put sellers actually want assignment when the stock is fundamentally attractive.

The only truly negative outcome is when the stock falls so far below the effective buy price that the position shows a meaningful unrealized loss on the shares. This is why stock selection is the foundation of a sound cash-secured put program: only sell puts on companies you would genuinely want to own at the strike price. Selling puts on stocks you do not want to own — purely to collect premium — exposes you to large losses with no good recovery path.

Traders who are assigned often then sell covered calls against the shares they received, a combined approach known as the wheel strategy. The premium from the covered call further reduces the cost basis until the shares are eventually called away at a profit, at which point the process restarts with a new cash-secured put.

The two most consequential decisions in a cash-secured put trade are the strike price and the expiration date. Both determine the premium you collect, the probability of assignment, and the capital efficiency of the trade.

Strike price selection: Out-of-the-money (OTM) puts — those with a strike below the current stock price — have a lower probability of assignment and therefore carry lower premiums. They are appropriate when you want maximum likelihood of keeping the premium without owning the stock. At-the-money (ATM) puts, where the strike equals the current price, carry the highest premium and roughly 50% assignment probability. In-the-money (ITM) puts, where the strike is above the current price, almost guarantee assignment and are used primarily when the investor urgently wants to acquire shares at a specific price. The calculator's assessment field categorizes your strike as Conservative (OTM by more than 15%), Moderate (OTM by 5–15%), Neutral (within 5% of current price), or Aggressive (ITM).

Expiration date selection: Most systematic put sellers focus on the 30–45 day expiration window. This range captures the steepest rate of theta decay — the erosion of an option's time value — while keeping trade duration short enough to reset quickly if conditions change. Options with less than 21 days to expiration can produce high annualized returns but require more active monitoring since gamma risk (rapid delta changes near expiration) increases. Options with 60 or more days to expiration collect more absolute premium but tie up capital for longer and produce lower annualized returns for equivalent risk.

Using the annualized return figure from this calculator, you can compare trades across different durations on a level playing field and identify which combination of strike and expiration offers the best risk-adjusted income for your capital.

A common question is: why sell a cash-secured put instead of simply placing a limit buy order at your target price? Both approaches result in owning the stock at a lower price — but they differ in a crucial way.

With a limit buy order, you acquire the stock only if the price reaches your limit. If the stock never drops to your target, you earn nothing on the cash you had set aside. With a cash-secured put, you earn the premium regardless of whether you are assigned. If the stock never drops to the strike, you pocket the income and your cash is returned — you effectively earn yield on the money while waiting.

This makes the cash-secured put superior in almost every scenario where you are willing to own the stock at or below the strike. The one exception is a scenario where the stock drops sharply and instantly — in that case, a limit order might fill at a better price than the effective buy price from the put. But statistically, for stocks that decline gradually, the cash-secured put consistently produces a lower average cost basis over time than passive limit orders.

The savings vs. target buy price field in the calculator quantifies this advantage directly. If your target is $48 and the effective buy price is $43 on a 1-contract trade, you are potentially saving $500 compared to your intended buy price, in addition to keeping the $200 premium if the put expires worthless. This dual benefit is the core of the cash-secured put's appeal for patient, stock-oriented investors.