Debit spread calculator
A debit spread costs money up front, and that cost is the most you can lose. Enter the strikes and the net debit to see your max gain, max loss and breakeven at expiration.
New to this? Read Buy to open vs sell to open, explained.
Worked example
Example numbers
Bull call spread: buy 1 call at the $100 strike and sell 1 call at the $105 strike, same expiration, for a net debit of $2.00.
At expiration: stock at $99 → both calls expire worthless, −$200. Stock at $103 → the $100 call is worth $3, the $105 call is worth $0, so 3.00 − 2.00 = +$100. Stock at $105 or higher → +$300, the max gain.
Bear put version: buy the $100 put and sell the $95 put for $1.80. Max loss $180, max gain (5.00 − 1.80) × 100 = $320, breakeven 100 − 1.80 = $98.20.
How the math works
- Max loss = debit × 100 × contracts (plus fees).
- Max gain = (width − debit) × 100 × contracts (minus fees).
- Breakeven = long strike + debit for a bull call, long strike − debit for a bear put.
FAQ
What is the max loss on a debit spread?
The net debit you paid times 100 shares per contract, plus fees. A spread bought for $2.00 can lose at most $200 per contract at expiration.
What is the max gain on a bull call spread?
The width between the strikes minus the debit, times 100. A $100/$105 call spread bought for $2.00 can make at most (5 − 2) × 100 = $300 per contract.
What is the breakeven on a debit spread?
For a bull call spread: the long call strike plus the debit. For a bear put spread: the long put strike minus the debit.
Why would a debit spread be cheaper than buying one option?
Selling the second option brings in premium that offsets part of the cost. In exchange, your gain is capped at the short strike.
Educational only. This page explains order mechanics with example numbers. It is not investment advice, not a recommendation to buy or sell anything, and not a broker. Check your own broker’s rules, fees and assignment terms before you trade.