Cash-Secured Put Calculator

How to use this calculator

A cash-secured put (CSP) is a bullish-to-neutral options trade. You sell a put on a stock you'd be willing to own at the strike. You collect premium up front. If the stock stays above your strike, the put expires worthless — you keep the premium and your collateral. If it drops below, you get assigned 100 shares per contract at the strike.

The math you need to evaluate any CSP:

Capital required: Strike × 100 × number of contracts. This is the cash you must keep secured.
Premium received: Premium per share × 100 × contracts. Goes into your account immediately.
Breakeven price: Strike minus premium received. The stock price at which you neither make nor lose money on assignment.
Cushion: (Spot − Strike) / Spot. The gap between the current price and your strike, expressed as a percentage. The framework calls for ≥5% cushion minimum.
Raw yield: Premium / strike. The total return on the trade if held to expiry.
Weekly cash-on-cash: Raw yield ÷ weeks to expiry. The single most important metric for CSP traders. Target ≥1.2%/week.
Annualized return: Weekly CoC × 52. Useful for comparing to other capital allocations.

The 1.2% rule: Below 1.2% weekly cash-on-cash, a CSP isn't worth the capital lockup. You're collecting roughly the same as a money market fund while accepting the downside risk of assignment. The framework's hard floor is 1.2%/wk, with a sweet spot of 1.5%/wk.

Going past raw math: The calculator above gives you the numbers. The Wheel Filter runs the same trade through 7 framework rules (universe, weekly yield, DTE, OI, delta, cushion, RSI) and gives you a green/yellow/red verdict — that's the level of discipline you actually need for consistent wheel trading.

Understanding the Cash-Secured Put Calculator

This calculator helps you size a cash-secured put (CSP) position, target the right strike and expiration, and project your cash-on-cash return. It enforces the framework's risk parameters so you avoid the common trap of chasing premium on positions you can't actually afford to be assigned on.

The Framework Rules

Wheel strategy practitioners rely on a small set of non-negotiable filters before entering a CSP. The institutional pattern looks like this:

Cash-on-cash target: approximately 1.2% weekly (roughly 60%+ annualized when redeployed)
Cushion: strike at least 5% below current stock price
DTE window: 7 to 23 days to expiration
Delta range: 0.30 to 0.50 (closer to 0.30 for conservative sizing)
Open interest: 100 or higher to ensure exit liquidity
Capital sizing: never commit more than you'd actually want assigned at the strike

The math behind cash-on-cash return is straightforward:

CoC % = (Premium received / Cash secured) x (7 / DTE) x 100
Cash secured = Strike price x 100

Worked Example

Assume AAPL trades at $200. You sell the 21-DTE $190 put for $2.40 per contract.

Cash secured: $190 x 100 = $19,000
Premium received: $2.40 x 100 = $240
Cushion: ($200 - $190) / $200 = 5.0% (meets the rule)
Period return: $240 / $19,000 = 1.26%
Weekly-equivalent CoC: 1.26% x (7 / 21) = 0.42% per week

That weekly figure is below the 1.2% target, so the framework would either pass on this trade or look at a different DTE/strike combination. Compare to a 14-DTE $192.50 put paying $2.30:

Cash secured: $19,250
Period return: $230 / $19,250 = 1.19%
Weekly CoC: 1.19% x (7 / 14) = 0.60% per week

Still under target. The calculator surfaces these comparisons instantly so you can rank candidates objectively.

Common Mistakes

Stretching delta past 0.50. That moves the position from "income trade" into "long stock proxy" without the upside.
Going below 7 DTE for yield. Gamma risk spikes inside the final week, and a single overnight gap can wipe weeks of premium.
Ignoring open interest. A wide bid-ask on a thinly traded contract destroys your edge before the trade opens.
Selling CSPs on tickers you would not own. The whole strategy depends on being indifferent to assignment.
Counting buying power instead of cash. A margin-relief calculation is not the same as cash secured. Size on full notional.

Bottom Line

A disciplined CSP setup pairs a 1.2% weekly CoC target with a 5% downside cushion, a 7-23 DTE window, delta between 0.30 and 0.50, and open interest of at least 100. If a candidate misses any of those filters, the framework moves on. Yield-chasing past these guardrails is the single most common reason wheel strategies blow up in volatile markets.

Educational only. Not investment, tax, or legal advice.