Calculator Inputs
Submit the form to show results above this form and directly below the header section.
Formula Used
Net premium debit per share = Long premium − Short premium
Total entry cost = (Net premium debit × Multiplier × Contracts) + (Commission × 2 × Contracts) + Other fees
Spread width per share = Absolute difference between strikes
Maximum spread value = Spread width × Multiplier × Contracts
Maximum profit = Maximum spread value − Total entry cost
Maximum loss = Total entry cost
Call spread breakeven = Long strike + Total entry cost ÷ (Multiplier × Contracts)
Put spread breakeven = Long strike − Total entry cost ÷ (Multiplier × Contracts)
Profit or loss at expiration = Spread value at expiration − Total entry cost
How to Use This Calculator
- Select either a bull call debit spread or bear put debit spread.
- Enter the long strike, short strike, and both option premiums.
- Set contracts, multiplier, commissions, and any extra fees.
- Enter the underlying price you want to test at expiration.
- Choose a scenario range and step size for the table and graph.
- Submit the form to view profit, loss, breakeven, chart, and downloadable reports.
Example Data Table
| Spread Type | Long Strike | Short Strike | Long Premium | Short Premium | Contracts | Multiplier | Total Entry Cost | Breakeven | Max Profit | Max Loss |
|---|---|---|---|---|---|---|---|---|---|---|
| Bull Call | 95 | 105 | $7.50 | $3.10 | 3 | 100 | $1,325.40 | 99.4180 | $1,674.60 | $1,325.40 |
| Bear Put | 110 | 100 | $8.20 | $4.00 | 2 | 100 | $843.60 | 105.7820 | $1,156.40 | $843.60 |
FAQs
1. What is a debit spread?
A debit spread combines buying one option and selling another in the same expiration. You pay a net premium upfront, and that debit defines the maximum possible loss if held to expiration.
2. Which spread types does this calculator support?
It supports bull call debit spreads and bear put debit spreads. Both are limited-risk strategies that benefit from directional movement while reducing upfront option cost through the short leg.
3. Why must the net premium be positive?
A positive net premium means you paid to enter the spread. If the short premium fully offsets or exceeds the long premium, the position becomes a credit spread, not a debit spread.
4. Does the calculator include commissions and fees?
Yes. It adds commission per contract for both legs and includes any extra fees you enter. Those costs increase total entry cost, reduce maximum profit, and shift breakeven.
5. How is breakeven calculated?
For call spreads, breakeven equals long strike plus net debit per share equivalent. For put spreads, breakeven equals long strike minus that same adjusted debit amount.
6. What does the payoff graph show?
The graph plots profit or loss across the underlying prices in your scenario range. It helps you see flat loss zones, the breakeven point, and the capped profit region.
7. Can I use a different contract multiplier?
Yes. Standard equity options often use 100, but the calculator lets you change the multiplier for adjusted contracts, mini contracts, or custom modeling.
8. Are these results guaranteed trading outcomes?
No. The calculator estimates expiration-based outcomes from your inputs. Real trading results can differ because of assignment, liquidity, slippage, changing volatility, and early closing decisions.