Iron Butterfly Calculator

What is an Iron Butterfly Strategy?

An iron butterfly (also called an "iron fly") is a neutral options strategy that combines a bull put spread and a bear call spread with the same center strike price. It consists of four options contracts with the same expiration date but three different strike prices.

The key difference between an iron butterfly and an iron condor is that the iron butterfly has both short options at the same strike price (the center), while the iron condor has the short put and short call at different strikes, creating a wider profit zone.

Short Iron Butterfly (Credit Strategy)

The most common variation, a Short Iron Butterfly, is entered for a net credit. It profits when the underlying asset's price stays at or near the center strike price at expiration.

• Structure: Sell ATM Put + Sell ATM Call (at center strike), Buy OTM Put + Buy OTM Call (at wing strikes)
• Max Profit: Net credit received (achieved when stock closes exactly at center strike)
• Max Loss: Wing width minus net credit (achieved when stock moves beyond either wing)
• Ideal Scenario: Low volatility, stock pins to center strike

Long Iron Butterfly (Debit Strategy)

A Long Iron Butterfly is the inverse strategy, entered for a net debit. It profits when the stock price moves significantly away from the center strike in either direction.

• Structure: Buy ATM Put + Buy ATM Call (at center strike), Sell OTM Put + Sell OTM Call (at wing strikes)
• Max Profit: Wing width minus net debit (achieved when stock moves beyond wings)
• Max Loss: Net debit paid (achieved when stock closes at center strike)
• Ideal Scenario: High volatility, significant price movement expected

How to Use This Calculator

This free iron butterfly calculator helps you visualize your risk and reward before entering a trade.

1. Select Position Type: Choose "Short" for income generation in neutral markets, or "Long" for volatility plays.
2. Enter Stock Price: The current trading price of the underlying asset.
3. Set Center Strike: Typically set at or near the current stock price (ATM) for maximum premium collection.
4. Define Wing Width: The distance from the center strike to the protective wing strikes. Wider wings mean more protection but lower credit received.
5. Enter Net Credit/Debit: The premium received (Short) or paid (Long) per share.

Iron Butterfly vs Iron Condor

Both strategies are neutral options strategies with defined risk, but they have key differences:

Key Considerations

• Implied Volatility: Short iron butterflies benefit from high IV at entry (more premium) and declining IV after entry.
• Time Decay: Theta works in favor of short iron butterflies, especially as expiration approaches.
• Assignment Risk: Short options at the center strike may be assigned early, especially around ex-dividend dates.
• Liquidity: Choose liquid underlyings with tight bid-ask spreads to minimize slippage.