Cash-Secured Put Calculator: Premium, Breakeven & Return

Enter your strike price, the premium income you expect and the days to expiration, and this cash secured put calculator returns the breakeven price, the cash you need to set aside and the annualized return for the strategy. You can weigh assignment risk before a single dollar is tied up.

How to Use the Cash Secured Put Calculator

Every field in this cash-secured put calculator maps to a line on your broker's order ticket, so you can fill it in straight from the trade you are considering. Enter the inputs below, run the numbers, then read the results from top to bottom before you risk a dollar. Change one input at a time to see which lever moves your result the most.

Strike price, premium received and number of contracts

Start with the option you are considering, pulled from the options chain for your ticker on your brokerage platform:

• Stock price: what the underlying stock trades for right now. It does not change your profit, but it shows how far the strike sits below the market.
• Strike price: the price at which you agree to buy if you are assigned. It drives the cash you must reserve.
• Premium received: what the buyer pays you per share. A $1.42 quote puts $142 in your account for each contract.
• Size: each contract covers 100 shares, so two of them cover 200 shares.

Days to expiration and stock price

The last input is DTE, the number of calendar days from today to the expiration date on the chain. It matters because a 2.5% gain earned in 38 days is worth far more than 2.5% earned in 90. The calculator uses it to annualize the result, so trades with different expiry dates land on one comparable scale.

What Is a Cash-Secured Put?

A cash-secured put is an options strategy in which you sell a put option and hold enough cash in the same account to buy the stock if you are assigned. You collect the premium up front. In exchange, you accept the obligation to buy 100 shares at the strike price if the stock finishes below it. The cash is what separates this trade from a naked put, where the seller has no cash set aside and relies on margin.

How a Cash-Secured Put Strategy Works

Once you sell to open the position, one of three things happens by the expiration date:

• The stock finishes above the strike. The option expires worthless, you keep the premium, and the cash is released for the next trade.
• The stock finishes below the strike. You are assigned, your cash buys the stock, and your entry price is the strike minus the premium received.
• You close early. A limit order to buy back the option ends the commitment, usually at a price below the premium received.

A cash-secured put strategy suits a neutral to moderately bullish outlook, where you expect the stock to hold steady or drift higher and the market to stay calm.

Who Sells Cash-Secured Puts and Why

Investors and traders reach for this cash-secured put strategy for a few reasons, and knowing yours changes which strike makes sense and how much risk you take. A patient investor wants a lower entry, an income-minded investor wants steady credits, and a trader wants a defined outcome:

• Buying a stock at a discount: pick a strike below today's price and get paid to wait for it to drop there.
• Income generation from idle cash that would otherwise sit in a savings sweep.
• Starting the wheel strategy, which begins with a short put and moves to covered calls after assignment.
• Expressing a bullish view with a defined commitment and a cushion below the market.

Cash-Secured Put Formulas and a Worked Example

Five short formulas cover everything a cash-secured put needs. In each one, \(K\) is the strike price, \(P\) is the premium per share, \(S\) is the stock price at expiration, \(N\) is the number of contracts and \(D\) is the DTE.

The cash to reserve is your strike price times 100 shares times the contracts you sell:

$$C = K \times 100 \times N$$

Premium income is your maximum profit, credited the moment the trade fills:

$$I = P \times 100 \times N$$

Breakeven price and effective cost basis

The breakeven at expiration is the strike price minus the premium received:

$$B = K - P$$

The same number is your effective cost basis if you are assigned, because the credit lowers what you pay for each share. Some brokers label it the effective purchase price, and you will also see it written as the break-even price. Below this level you are underwater on the position, and above it you are not, even after the stock lands in your account.

Annualized return for comparing expirations

The annualized return scales your premium to a full year so you can rank trades of different lengths:

$$R_{a} = \frac{P}{K} \times \frac{365}{D} \times 100$$

The first fraction is your return on capital for the trade, and the strike price sits in the denominator because it is the cash you reserved. A shorter option that pays the same premium annualizes higher, which is why many sellers favor 20 to 45 days. Your cash-secured put return looks modest on a single trade and adds up across a year of them.

A worked example with two puts

Say a stock trades at $61.20 and you sell two of the $57.50 puts for $1.42 each, with 38 days left until expiry. Here is what the calculator returns:

• Cash required: $57.50 × 100 × 2 = $11,500
• Premium income: $1.42 × 100 × 2 = $284, also your net credit
• Breakeven: $57.50 − $1.42 = $56.08
• Return on capital: $1.42 ÷ $57.50 = 2.47%
• Annualized return: 2.47% × (365 ÷ 38) = 23.72%
• Maximum loss: ($57.50 − $1.42) × 200 = $11,216, reached only if the stock falls to zero

Your downside buffer, the distance from today's $61.20 down to the $56.08 break-even, is 8.37%. The stock can fall by that much before this trade loses a dollar at expiration.

Cash-Secured Put Assignment Risk and Effective Cost Basis

The risk of assignment is the price you pay for the premium in every cash-secured put. If the stock ends below your strike, the buyer chooses to exercise the option, and your broker uses the reserved cash to buy 100 shares for every option you sold. That is a fair outcome only when you truly wanted it at that price.

What happens if you are assigned?

You now own 200 shares with a $56.08 cost basis each, or $11,216 in total, even if the market price is lower. Your loss on the position is the gap between that cost basis and the current stock price. Many investors see assignment as a planned entry rather than a failure, because they chose a stock and a price they liked before they sold the cash-secured put.

When the put expires worthless

If the stock closes at or above $57.50, a cash-secured put like this one expires worthless and the $284 is yours to keep. The obligation ends, the cash returns to your buying power, and you can sell another option on the same name or a different one.

Cash-Secured Put Payoff at Expiration

Cash-secured put profit is capped at the premium, while the loss depends on where the stock finishes against your strike. The formula below covers any position size:

$$\text{P/L} = \left(P - \max(K - S, 0)\right) \times 100 \times N$$

Cash-Secured Put Payoff Diagram

This chart plots that formula across a range of stock prices. Notice the flat line on the right and the steep slope on the left: your gain stops at the premium, while each dollar below the breakeven costs $200 across two puts.

Maximum profit and maximum loss

Your max profit on a cash-secured put is the premium, $284 here, and you earn it whenever the stock closes at or above the strike. Your max loss is the strike minus the premium, times the 100-share multiplier and your position size. At $11,216, that is a downside risk to respect, even though it happens only if the stock goes to zero.

Checking a $200 Strike Before You Place the Order

Dana has $24,500 in settled cash and wants to own a stock that closed at $212.35. Buying today feels rich, so Dana looks at the 45-day expiration on the option chain and finds the $200 put bid at $3.64, with a delta of 0.21.

Into the calculator go a $212.35 stock price, a $200 strike, $3.64 of premium, one contract and 45 days. The results come back in a heartbeat:

• Cash required: $20,000, or 81.6% of the account, leaving $4,500 free
• Premium income: $364
• Breakeven: $196.36, which is 7.53% below today's price
• Return on capital: 1.82%, or 14.76% annualized

Two references frame the decision. A delta of 0.21 means roughly a 21% chance of finishing in the money, inside the 0.20 to 0.30 band many sellers use as a ceiling. And Dana's own floor is 12% annualized, which the 14.76% clears.

Then Dana reruns the numbers with one input changed: the $195 strike, quoted at $2.31. It needs $19,500 and breaks even at $192.69, but it annualizes to only 9.61%, under the 12% floor. The $200 strike stays.

The last check is the bad case. If the stock closes at $188, the position loses $836 at expiration, but Dana would own it at an effective $196.36, a price already chosen in advance. That is the trade Dana places: one $200 put, a limit order at $3.64, and a calendar reminder for the day before expiry to decide between rolling and letting it go.

How to Choose a Strike Price and Expiration Date for Options Income

A higher strike price pays more premium and raises the odds of assignment, and a lower strike price does the reverse. Run each candidate through the cash-secured put calculator and compare the yearly yield, not just the credit. Use this table as a starting point for weighing that credit against the chance of owning the stock:

Time decay and theta

Time decay works in your favor because, as the seller, you are the trader on the winning side of the clock. Theta measures how much value a put option loses each day, and time decay accelerates in the last few weeks of the option's life. Selling a cash-secured put 20 to 45 days out captures the fastest decay, especially when volatility is elevated, while leaving room to adjust if the market turns.

• Shorter options pay less in total but annualize higher.
• Longer options pay more in total but tie up your cash for months.
• Time decay speeds up as the end approaches, so the last weeks are where most of the value disappears.

Out-of-the-money strikes and delta

An option that is out-of-the-money has a strike below the current stock price. Delta gives a rough odds gauge: a delta near 0.20 means about a one-in-five chance of finishing in the money. Volatility is the biggest driver of option premium, and higher implied volatility raises what you collect while also signaling a wider range of stock prices, so treat a fat credit as a warning as much as a reward.

• Check the underlying stock's recent trend before choosing a strike price.
• Compare implied volatility against the stock's usual range.
• Watch for volatility spikes around earnings and news, when put options get expensive for a reason.
• Read the option chain for volume and open interest, since a thin market means wide spreads.

Selling Puts and the Wheel Strategy

This trade is the first half of the wheel strategy, an income cycle that starts with a cash-secured put and continues with calls written on the assigned position. It rewards patience and stocks you would own anyway.

Wheel strategy step by step

1. Sell a cash-secured put on a stock you want to own and collect the premium.
2. If it expires worthless, keep the credit and sell another option.
3. If you are assigned, you own the shares at your entry price.
4. Sell a covered call against that position, then repeat until it is called away.

Selling covered calls on your new shares

After assignment, a covered call lets you collect more premium on the shares you now hold. A strike at or above your entry price means that if the stock is called away, you exit with a profit. Model that second leg with a covered call calculator before you commit.

Covered Call vs. Cash-Secured Puts

Both trades collect premium, cap your upside and leave you exposed to downside risk if prices keep falling. The difference is what you hold when you start: cash for the put, stock for the call. The cash-secured put options strategy needs cash to spare. Cash-secured puts therefore suit an investor with idle cash, while covered calls suit one who already owns the stock.

Cash-Secured Put Strategy vs Buying Shares Outright

Buying 200 shares at $61.20 costs $12,240 and pays you nothing while you wait. The cash-secured put strategy pays $284 to wait for a lower entry of $56.08, a built-in discount to today's price, but you give up the gains if the stock runs away without you. Choose the option when you are willing to wait, and the shares when you would hate to miss the move.

• The trade lowers your entry price by the premium received and pays you to wait.
• Owning the position outright captures every dollar of upside and collects a dividend if one is declared.
• Both lose money if the price keeps falling, though the option loses less by the amount of the premium.

Full margin versus cash required

The cash you reserve is the full strike price times 100 for every option sold. Some brokers let you reserve less on margin, which boosts your yield. A half margin approach doubles the gain on paper, and it also doubles the leverage and the risk if the trade goes wrong, so many sellers stay with the full amount as cash collateral for this strategy.

Common Mistakes When You Sell a Put

Put selling looks like easy income until one bad week erases a year of credits. Options trading rewards a plan more than a hunch, and most losses in cash-secured puts come from a few repeatable errors:

• Selling puts on a stock you would not want to own, chasing a high premium on weak fundamentals.
• Ignoring earnings dates, when a gap-down can leap right past your strike.
• Selling into a confirmed downtrend because the payout looks generous.
• Committing too much capital to one name, which undermines diversification across your portfolio.
• Underestimating the capital requirement, or the capital at risk when the stock gaps lower.
• Skipping an exit plan, so the position runs to assignment by default rather than by choice.
• Misjudging volatility, then selling because the credit looks rich only when the stock is about to move.
• Overlooking the opportunity cost of cash that could earn interest elsewhere.

Good risk management starts with sizing: reserve only the share of your portfolio you could comfortably own at the strike. Gamma, vega and rho complete the Greeks, but for most traders delta and theta do most of the work. Stick with stocks you already follow, and avoid names where you cannot say why you would want them.

CSP Calculator Limits, Taxes and Fees

Like any options income calculator, this CSP calculator is a static expiration model built for educational use, not financial advice. To see profit across every price, an options profit calculator or a put option calculator can chart the full curve. Keep in mind what a simple model of the strategy leaves out, since it changes the risk you actually carry.

Commissions and taxes

A commission of a few dollars per trade and any exchange fees come off your net credit, and a busy month of small trades can shave your yield noticeably. Tax treatment matters too: in the United States, premium from a put that lapses unexercised is generally taxed as a short-term capital gain, while premium from an assigned put lowers your purchase price on the stock. Ask a tax professional how your account is treated.

Early assignment and dividends

American-style put options can be exercised before expiration, and a deep in-the-money position is the likeliest candidate. The calculator assumes assignment happens only at expiration. It also leaves out dividends, liquidity, margin interest and any difference in static return across accounts, so confirm collateral rules and pricing with your brokerage before you place the trade.