Butterfly Spread Profit Calculator
A long butterfly is a defined-risk, low-cost options strategy built from three equally spaced strikes: buy one lower, sell two in the middle, buy one upper, all the same type and expiration. It pays off most when the underlying lands precisely at the middle strike and risks only the net debit paid. This calculator takes the lower strike, the equal wing width, the net debit per share, and the contract multiplier, then returns maximum profit, maximum loss, both breakeven prices, and return on risk.
Butterfly spread formula
Middle strike = lower strike + wing width
Max profit = (wing width - net debit per share) * multiplier
Max loss = net debit per share * multiplier
Lower breakeven = lower strike + net debit per share
Upper breakeven = (lower strike + 2 * wing width) - net debit per share
Return on risk = max profit / max loss * 100
Peak profit occurs at the middle strike. The net debit must be less than the wing width for the trade to have any profit potential; otherwise it cannot pay off.
Using the result
- The butterfly wins on a precise, low-volatility outcome near the middle strike.
- Wider wings raise the maximum profit but usually cost a larger debit.
- Maximum loss is always capped at the debit paid, making the strategy defined-risk.
- The profit zone lies strictly between the two breakeven prices.
- Add commissions across all four legs for a precise live-trade result.
Butterfly spread: frequently asked questions
What is a long butterfly spread?
A long butterfly buys one lower-strike option, sells two middle-strike options, and buys one higher-strike option, all of the same type and expiration with equal strike spacing. It is a debit, defined-risk strategy that profits most when the underlying expires exactly at the middle strike.
How do you calculate butterfly max profit?
Maximum profit equals the wing width (the distance between adjacent strikes) minus the net debit paid per share, times the contract multiplier. It is realized only if the underlying finishes exactly at the middle strike at expiration, where the short options expire worthless and the lower long option is fully in the money.
What is the maximum loss on a butterfly?
The maximum loss on a long butterfly is the net debit paid, times the contract multiplier. It occurs when the underlying expires at or below the lowest strike or at or above the highest strike, leaving the spread worthless. Because it is a debit strategy, you cannot lose more than you paid.
What are the breakeven points of a butterfly?
A long butterfly has two breakevens. The lower breakeven is the lowest strike plus the net debit per share. The upper breakeven is the highest strike minus the net debit per share. The position is profitable only when the underlying expires between these two prices.
Does this assume equal strike spacing?
Yes. This calculator uses a single wing width applied symmetrically: the middle strike sits one wing width above the lower strike, and the upper strike sits one wing width above the middle strike. Unbalanced or broken-wing butterflies have different payoff geometry and should be modeled separately.
Official sources
- U.S. SEC Investor.gov: Options glossary.
- The Options Clearing Corporation (OCC): Standardized options education.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.