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.
How to Use This Calculator
Four inputs and the calculator handles the rest. Results update instantly as you type.
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.
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.
Enter contract count
Enter how many contracts you are trading. Each contract covers 100 shares, so profit, loss, and cost figures scale accordingly.
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.
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.
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Track your diagonal spread trades over time
This calculator shows your setup before the trade. The next step is tracking whether your diagonal spreads are actually profitable over time. Enter your email to get the free Financial Tech Wiz trading journal and all included tools.
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