Diagonal Spread Calculator
Calculate the net debit and maximum loss for a diagonal spread. This strategy combines a calendar and vertical spread to profit from time decay and moderate directional moves.
Enter your diagonal spread details above, then click Calculate Spread to see net debit, max loss, and strategy notes.
For educational purposes only. Not financial advice. Read full disclaimer
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Diagonal Spread Formulas
Net Debit = (Long Premium - Short Premium) x 100 x Contracts
Max Loss = Net Debit (if both options expire worthless)
Max Profit = Variable (depends on IV and time at short expiry)
Breakeven = Variable (depends on long option residual value)
Worked Examples
Example 1: AAPL Diagonal Call Spread
AAPL is trading at $175. You buy the 175 call expiring in 60 days for $8.00 and sell the 180 call expiring in 30 days for $3.00 (1 contract).
- Net Debit = (8.00 - 3.00) x 100 = $500
- Max Loss = $500 (if AAPL drops significantly and both options expire worthless)
- Best case: AAPL near $180 at short expiry — short call expires worthless, long call retains substantial value
Example 2: SPY Diagonal — 2 Contracts
SPY is at $450. You buy the 448 call (45 DTE) for $10.00 and sell the 455 call (14 DTE) for $3.50 (2 contracts).
- Net Debit = (10.00 - 3.50) x 100 x 2 = $1,300
- Max Loss = $1,300
- If SPY closes at $455 at short expiry, the short call expires ATM and the long call has ~31 days of time value remaining
How to Use This Calculator
- Enter the long call strike — the strike of the longer-dated option you are buying.
- Enter the short call strike — the strike of the shorter-dated option you are selling (usually higher).
- Enter the long premium — the per-share price you pay for the longer-dated call.
- Enter the short premium — the per-share credit you receive for selling the shorter-dated call.
- Set the number of contracts — each contract covers 100 shares.
- Click Calculate Spread — review net debit, max loss, and strategy guidance.
Frequently Asked Questions
- What is a diagonal spread?
- A diagonal spread combines elements of a vertical spread and a calendar spread. You buy a longer-dated option at one strike and sell a shorter-dated option at a different strike. This gives you exposure to both directional movement and time decay, making it a versatile strategy.
- Why is max profit variable on a diagonal spread?
- Because the two options have different expiration dates, the long option still has time value when the short option expires. The exact profit depends on implied volatility, time remaining on the long leg, and where the underlying price is at the short option's expiration. You cannot know these values in advance.
- What is the ideal scenario for a diagonal spread?
- The ideal outcome is for the underlying to close near the short strike at the short option's expiration. This lets the short call expire worthless (keeping the full premium) while the long call retains significant time value that you can sell or hold.
- How does implied volatility affect a diagonal spread?
- Rising IV generally helps because the long option (with more time) has higher vega than the short option. If IV increases after you enter, the long leg gains more value than the short leg costs to buy back. Conversely, falling IV hurts the position.
- Can I use puts instead of calls for a diagonal spread?
- Yes. A diagonal put spread works the same way — buy a longer-dated put and sell a shorter-dated put at a different strike. Put diagonals are typically used for bearish outlooks, while call diagonals suit bullish or neutral-to-bullish views.