Cash-Secured Put Calculator
Sell a put and you get paid up front to wait for a lower entry on a stock you want anyway. Enter the strike, the premium and your contracts for your premium income, static and annualized yield, the capital you tie up, your effective buy price and how much downside cushion the premium buys you.
Selling a cash-secured put means you set aside the full cash to buy 100 shares per contract at the strike. You keep the premium; if the stock closes below the strike at expiration you buy the shares at the strike — at an effective price reduced by the premium you received.
Cash-secured put outcome
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How to use the calculator
- Enter the put strike you are selling and the premium received per share.
- Enter the number of contracts — each obligates you to buy 100 shares if assigned.
- Optionally add days to expiration to see your static yield expressed as an annualized figure.
- Read your premium income, capital secured, static and annualized yield, effective buy price and downside protection.
How a cash-secured put pays you
Selling a cash-secured put means you agree to buy 100 shares per contract at the strike price, and you set aside the full cash to do so. In return, you collect a premium up front that is yours to keep. If the stock stays above the strike at expiration, the put expires worthless — you keep the premium and never buy the shares. If it falls below the strike, you buy at the strike, but your effective cost is reduced by the premium you already received.
The two numbers to weigh are your static yield — the premium as a percentage of the capital you secure — and your effective buy price, which is the strike minus the premium. Annualizing the yield lets you compare puts of different durations fairly, though it assumes you can repeat the trade continuously, which is an idealization rather than a promise.
A cash-secured put is often the first half of the “wheel” strategy: sell puts until assigned, then sell covered calls on the shares you now own. It generates income and can lower your entry price, but it is not downside protection — below the effective buy price you lose exactly as a shareholder would. The one rule that matters: only sell puts at strikes where you would actually be glad to own the shares.
Frequently asked questions
How is cash-secured put yield calculated?
Static yield is the premium received divided by the strike price — the return on the cash you set aside if the put expires worthless. For example, a $2 premium on a $100 strike is a 2% static yield. Enter days to expiration and the calculator annualizes it (static yield × 365 ÷ days) so you can compare a 30-day put against a 45-day put on the same basis. Annualized figures assume you could repeat the trade all year, which real markets rarely allow.
What is the breakeven or effective buy price on a cash-secured put?
It is the strike price minus the premium you received. If you are assigned the shares, that is your effective cost per share — lower than buying at the strike because the premium offsets it. Above that price you never lose money; below it you lose exactly as an owner of the stock would, cushioned by the premium.
How much capital does a cash-secured put tie up?
The full amount needed to buy the shares if assigned: strike × 100 × contracts. A $100 strike on one contract secures $10,000. That cash is set aside as collateral for the length of the trade, which is what makes it 'cash-secured' rather than a naked put — you can always honour the obligation to buy.
What is the downside and risk of selling a cash-secured put?
The premium gives a cushion equal to premium ÷ strike, but it does not protect against a large decline. Your worst case is the stock going to zero, an identical downside to owning the shares outright at the effective buy price. Sell puts only at strikes where you would genuinely be happy to own the stock, and size the position so assignment never overcommits your account.
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Educational tool only — not financial advice. Options involve substantial risk and are not suitable for all investors. Nothing here promises a return. Also see our trading blog.