Ratio Spread Calculator: Front Ratio and Backspread

Unequal option quantities at expiration

Ratio Spread Calculator

Calculate call or put front ratio spreads and backspreads with a custom 1:N ratio. See net entry, profit or loss, break-even prices, defined or unlimited outcomes and a full expiration payoff table.

For puts, the one-contract leg uses the higher strike.
All legs use the same expiration and multiplier.
Formatting only; no exchange-rate conversion.
Use 0 to inspect the downside boundary.
Premium per share.
Premium per share.
Whole number from 2 to 10.
Opening and expiration costs for all legs.

Profit / loss at entered price
Net entry
Maximum profit
Maximum loss
Break-even result
Result below lower strike
Result at lower strike
Result at upper strike
High-side outcome
Return on defined maximum loss

Expiration payoff

Stock pricePosition intrinsic valueProfit / loss after fees

Unlimited outcomes describe the mathematical expiration payoff. They are not probabilities, margin requirements or recommendations.

What is a ratio spread?

A ratio spread uses different quantities at two strikes, commonly one option at one strike and two options at another. This calculator consolidates call ratio spreads, put ratio spreads, call ratio backspreads and put ratio backspreads in one tool. It accepts ratios from 1:2 through 1:10.

A front ratio spread owns the one-contract leg and sells N options at the other strike. A backspread reverses those quantities. Because the legs are unequal, some structures contain uncovered short options and can have unlimited risk.

Ratio spread formulas

Net entry = (lower quantity × lower premium + upper quantity × upper premium) × spreads × multiplier + fees
Profit at expiration = position intrinsic value × spreads × multiplier − net entry

For calls, intrinsic value is max(stock price − strike, 0). For puts, it is max(strike − stock price, 0). The quantity signs depend on the selected structure: front call = +1 lower/−N upper; front put = −N lower/+1 upper; call backspread = −1 lower/+N upper; put backspread = +N lower/−1 upper.

Verified 1:2 call front ratio example

Buy one US$100 call for US$7 and sell two US$110 calls for US$3 each. With one spread, a 100-share multiplier and US$4 in fees, the net debit is US$104. At a US$105 stock price the profit is US$396. Maximum profit is US$896 at US$110, break-even prices are US$101.04 and US$118.96, and loss above the second break-even is unlimited.

How to interpret the results

  • Net debit or credit includes all entered fees and every option quantity.
  • Maximum outcomes consider stock-price boundaries, both strikes and the high-price tail.
  • Break-even result may contain zero, one or two prices, or a zero-profit range when an outside plateau is exactly zero.
  • Return on defined maximum loss is omitted when risk is unlimited or the entered prices imply no loss.

Assumptions and limits

  • Both options have the same expiration, type and contract multiplier; only strikes, premiums and quantities differ.
  • The model is expiration-only and excludes time value, volatility changes, early assignment, dividends, taxes, bid/ask spreads, slippage and broker margin.
  • Premiums are per share and should come from the same market snapshot. The display currency does not convert values.
  • American-style short options can be assigned before expiration. Uncovered legs can require substantial collateral.

Risk warning: a front call ratio spread can lose without limit as the stock rises. Other ratio structures can also create large or asymmetric losses. Confirm the exact legs and broker requirements before trading.

Related calculators

Use the Option Debit Spread Calculator for 1:1 long verticals; the Option Credit Spread Calculator for 1:1 short verticals; the Broken Wing Butterfly Calculator for a three-strike 1:2:1 structure; and the Options Profit Calculator for one option.