Calculator Inputs
Payoff Chart
The chart plots total profit or loss at expiry across your chosen underlying price range.
Example Data Table
| Scenario | Option Type | Spread | K1 | K2 | K3 | Net Debit/Credit per Unit | Spot at Expiry | Total P/L |
|---|---|---|---|---|---|---|---|---|
| Example A | Call | Long | 90 | 100 | 110 | 1.00 Debit | 100 | 900.00 |
| Example B | Put | Long | 90 | 100 | 110 | 1.50 Debit | 95 | 350.00 |
| Example C | Call | Short | 80 | 90 | 100 | 2.00 Credit | 90 | -800.00 |
Formula Used
(Intrinsic at K1 − 2 × Intrinsic at K2 + Intrinsic at K3) − Net Debit
−Intrinsic at K1 + 2 × Intrinsic at K2 − Intrinsic at K3 + Net Credit
max(S − K, 0)
max(K − S, 0)
Payoff per unit × Contracts × Multiplier − Commission
For symmetrical butterflies, the long spread breakevens are usually K1 + net debit and K3 − net debit. The short spread uses the net credit instead. Maximum values are easiest to interpret when K2 sits exactly halfway between K1 and K3.
How to Use This Calculator
- Choose whether the structure uses calls or puts.
- Select long butterfly or short butterfly.
- Enter three ordered strikes where K1 < K2 < K3.
- Input the premium paid or received for each strike.
- Set contracts, multiplier, and total commissions.
- Enter the expiry spot price for the main result.
- Define a chart range and step size.
- Press calculate to view metrics, graph, and downloads.
Frequently Asked Questions
1. What does a butterfly spread measure?
It measures how a three-strike option structure behaves at expiry. The calculator shows profit, loss, breakevens, and the payoff shape across a selected range of underlying prices.
2. What is the difference between long and short butterfly?
A long butterfly usually seeks peak profit near the middle strike. A short butterfly flips that profile, often benefiting when price moves away from the center.
3. Can I use call and put butterflies here?
Yes. The calculator supports both call-based and put-based butterflies. It applies the correct intrinsic value formula for each option type automatically.
4. Why do the breakevens sometimes show custom width?
Closed-form breakeven formulas are most direct when the strike distances are equal. Unequal wing widths can still be modeled, but the chart becomes the better guide.
5. What role does the contract multiplier play?
The multiplier scales every per-unit payoff into total currency exposure. A standard equity option often uses 100, but your market can use a different contract size.
6. Does commission affect maximum profit and loss?
Yes. This page subtracts the total commission from final results. That makes the displayed profit smaller and the displayed loss larger than the no-fee case.
7. Why is the middle strike important?
The middle strike is the peak zone for a standard long butterfly. It is also the point where the short butterfly often reaches its deepest loss area.
8. What do the CSV and PDF downloads include?
They include the generated price-versus-profit table used for the chart. This helps with record keeping, reporting, and offline review of modeled outcomes.