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Diagonal Spread Calculator

Model your diagonal spread before you place it. Enter your long and short strikes and premiums to instantly see max profit, max loss, breakeven, and a full P&L diagram.

Different Strikes & Expirations Directional Bias Defined Max Loss Interactive P&L Diagram

Underlying Asset

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Strategy Template (optional — pre-fills legs below)

Option Legs

Legs with different expirations are supported (calendar spreads). Implied Vol % is used by the Black-Scholes engine for theoretical pricing.


How to Use This Calculator

Four inputs and the calculator handles the rest. Results update instantly as you type.

1

Enter the long option

Enter the strike and premium paid for the longer-dated option you are buying. For a bullish call diagonal, this is typically an in-the-money or at-the-money call with a longer expiration date.

2

Enter the short option

Enter the strike and premium received for the shorter-dated option you are selling. For a call diagonal, this is typically an out-of-the-money call nearer to expiration. The credit reduces your net debit.

3

Enter contract count

Enter how many contracts you are trading. Each contract covers 100 shares, so profit, loss, and cost figures scale accordingly.

4

Review your results

The calculator instantly shows your net debit, max profit, max loss, and breakeven, plus a full P&L diagram covering every possible stock price at the short option’s expiration.


Understanding the Diagonal Spread

Key numbers every diagonal spread trader needs to know before entering the position.

Max Profit
(Short Strike − Long Strike) − Net Debit
Achieved when the stock closes at or above the short call strike at front-month expiration. The spread reaches its maximum value when the full width is captured minus the net debit you paid to enter.
Max Loss
Net Debit Paid
Occurs if the stock drops sharply and both options expire worthless, or if the spread collapses in an unfavorable environment. Your loss is fully capped at what you paid to enter the position.
Breakeven at Expiration
Long Strike + Net Debit
The approximate stock price at which the position breaks even at the short option’s expiration. The exact level varies with implied volatility and time remaining in the back-month option at expiration.

The diagonal spread earns its name from the way it appears on an options chain: moving diagonally across both the strike column and the expiration column. By combining different strikes and different expirations, the strategy layers a directional view on top of a time decay structure. The short front-month option decays faster than the long back-month option, giving you a built-in theta advantage while you wait for the stock to move in your favor.

For a bullish call diagonal, you want the stock to drift higher and close near or above the short call strike at front-month expiration. If it does, the short call expires worthless, you capture the full premium, and the long back-month call has appreciated in value. You can then sell another short-term call against the remaining long leg, repeating the cycle to reduce your net debit further each expiration.

One important check before entering any diagonal: confirm that the spread width (short strike minus long strike) is greater than the net debit. If the spread width is less than the net debit, the maximum profit would be negative, making the trade not worth taking at those prices.


Diagonal Spread Example Trade

XYZ is trading at $100. You buy a 60-day $95 call for $8.00 and sell a 30-day $105 call for $2.00.

Position Summary (Call Diagonal)
Stock Price$100.00
Long Call Strike (60-day)$95.00
Long Call Premium Paid−$8.00 / share (−$800)
Short Call Strike (30-day)$105.00
Short Call Premium Received+$2.00 / share (+$200)
Net Debit−$6.00 / share (−$600)
Spread Width$10.00 ($105 − $95)
Max Profit~+$400 (if stock ≥ $105 at 30-day expiry)
Max Loss−$600 (net debit)
Breakeven~$101.00 ($95 + $6.00)
After Short Expires WorthlessStill hold 30-day $95 call — sell another short-term call

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Diagonal Spread — Common Questions

A diagonal spread is an options strategy that uses different strike prices and different expiration dates. You buy a longer-dated option at one strike and sell a shorter-dated option at a different strike, blending the time decay benefit of a calendar spread with the directional exposure of a vertical spread. The most common version is a bullish call diagonal: buy a lower-strike back-month call and sell a higher-strike front-month call. A bearish put diagonal works in the opposite direction. The poor man’s covered call is a well-known example of a call diagonal spread.
The maximum profit on a call diagonal spread is approximately the spread width (short strike minus long strike) minus the net debit paid. For example, with a $95 long call and a $105 short call, the spread width is $10. If the net debit is $6.00, max profit is roughly $4.00 per share, or $400 per contract. This is achieved when the stock closes at or above the short call strike at front-month expiration. The exact figure varies with implied volatility and the time value remaining in the back-month option at expiration.
The maximum loss on a diagonal spread is the net debit paid to enter the position. This occurs when the stock falls sharply and both options expire worthless, or when the spread collapses to near zero in an unfavorable scenario. For example, if your net debit is $6.00 per share, your maximum loss is $600 per contract. Because diagonal spreads are entered for a net debit, risk is fully defined from the moment you place the trade.
The approximate breakeven on a call diagonal spread is the long call strike plus the net debit paid. For example, with a $95 long call and a net debit of $6.00, the breakeven is approximately $101.00. The exact breakeven depends on implied volatility and time remaining in the back-month option at expiration, so it is an estimate rather than a fixed price. The stock needs to be above the breakeven at the short option’s expiration for the trade to be profitable at that cycle.
A calendar spread uses the same strike price for both legs, differing only in expiration date. A diagonal spread uses both different strike prices and different expiration dates, giving it a directional component that a calendar spread lacks. A calendar spread profits most when the stock stays right at the shared strike. A diagonal spread can be structured to profit from a directional move — a bullish call diagonal profits when the stock rises toward or above the short strike, while a bearish put diagonal profits when the stock falls toward or below the short put strike.