An iron butterfly is a four-leg options strategy that collects a premium upfront and profits most when the underlying asset closes at or very near the short strike at expiration. It combines a short straddle at the money with a long strangle outside that center strike to cap the maximum loss on both sides. The result is a defined-risk, defined-reward trade with a narrow profit zone and a clear breakeven formula you can calculate before entering the position.

Knowing the exact numbers before you place a trade (max profit, max loss, and both breakeven prices) is where an iron butterfly calculator becomes useful. This guide walks through how the strategy is built, how the payoff math works, and what conditions make it worth modeling.

What Is an Iron Butterfly Options Strategy?

The iron butterfly belongs to the family of multi-leg options spreads designed to profit from low realized volatility. At its core, it involves selling an at-the-money straddle and buying a strangle further out to define the maximum loss. Traders use it when they expect the underlying asset to stay within a tight range through expiration and when options premiums are elevated enough to make the credit worthwhile to model.

How an Iron Butterfly Is Constructed

An iron butterfly is built from four options contracts, all sharing the same underlying asset and expiration date:

• Sell one ATM call (at the money, center strike)
• Sell one ATM put (same strike as the short call)
• Buy one OTM call (out of the money, above center strike)
• Buy one OTM put (out of the money, below center strike)

The two short options form a short straddle at the center strike. The two long options act as wings that define the maximum loss. When the wings are equidistant from the center strike (for example, $10 above and $10 below), the structure is symmetric. Asymmetric versions exist, but the standard iron butterfly uses equal wing widths.

The strategy opens for a net credit: the premiums collected on the two short legs exceed the cost of the two long legs. That net credit is also the maximum profit, realized only when the stock closes exactly at the center strike at expiration.

Iron Butterfly Payoff: Max Profit, Max Loss, and Breakevens

Worked example

Suppose a stock is trading at $100 with 21 days to expiration. Here is one possible set of strikes and premiums:

Leg	Action	Strike	Premium
Short call	Sell	$100	+$4.00
Short put	Sell	$100	+$4.00
Long call	Buy	$110	-$1.00
Long put	Buy	$90	-$1.00

Net credit

Net credit = (short call + short put) – (long call + long put)
Net credit = ($4.00 + $4.00) – ($1.00 + $1.00) = $6.00 per share ($600 per contract)

Maximum profit

Maximum profit equals the net credit collected, achieved when the stock closes exactly at the short strike ($100) at expiration. Both short options expire worthless, both long options expire worthless, and the full $6.00 credit is kept.

Max profit = $6.00 per share ($600 per contract)

Maximum loss

Maximum loss occurs when the stock moves beyond either long strike by expiration. It equals the wing width minus the net credit.

Max loss = Wing width – Net credit = $10.00 – $6.00 = $4.00 per share ($400 per contract)

This loss is realized at or below $90 or at or above $110.

Breakeven prices

The iron butterfly has two breakeven prices:

Upper breakeven = Center strike + Net credit = $100 + $6.00 = $106.00
Lower breakeven = Center strike – Net credit = $100 – $6.00 = $94.00

The stock must stay between $94 and $106 for the trade to be profitable at expiration. Entering different strikes and premiums into the free iron butterfly calculator instantly shows the payoff across all scenarios.

When Traders Use an Iron Butterfly

The iron butterfly is a short-volatility trade. It collects the most premium when implied volatility is elevated and profits when actual price movement stays tighter than the market expected. Traders typically look at this structure when:

• Implied volatility is high relative to recent realized volatility, meaning the options market is pricing in movement that may not materialize.
• A stock or index is near a level of strong consolidation and appears likely to stay range-bound through expiration.
• An earnings event or catalyst has just passed and a large move seems less probable.

The narrow profit zone is the central tradeoff. Unlike a wide iron condor, the iron butterfly requires the stock to land very close to the center strike to capture the full credit. In exchange for that tighter target, the butterfly typically collects a larger credit relative to its wing width than a condor does at similar strikes.

Iron Butterfly vs. Iron Condor

The two strategies are closely related. Both involve selling two options near the current price and buying two options further out as protection. The key structural difference is whether the short strikes are the same (butterfly) or separated (condor).

Feature	Iron Butterfly	Iron Condor
Short strikes	Same (ATM)	Separated (OTM call / OTM put)
Profit zone	Narrow, centered on ATM strike	Wider range between short strikes
Net credit	Higher relative to wing width	Lower relative to wing width
Max profit probability	Lower (stock must pin ATM)	Higher (wider profit target)
Breakeven range	Tighter	Wider

The choice between the two depends on how tight the expected range is and what credit-to-risk ratio fits the setup being modeled. The iron condor calculator and the iron butterfly calculator can be used in parallel to compare payoff profiles before deciding which structure fits the situation.

Iron Butterfly vs. Long Butterfly

The iron butterfly should not be confused with a long call butterfly or long put butterfly. Those structures involve only calls or only puts, use three strikes instead of four legs, and typically cost a debit rather than collecting a credit. The mechanics are similar in that both profit when the stock pins the center strike, but the construction and risk profile differ.

The butterfly spread calculator handles the long call and long put butterfly variations if you want to compare them against the iron butterfly’s payoff.

Iron Butterfly vs. Short Straddle

An iron butterfly is essentially a short straddle with wings added for protection. The short straddle (selling an ATM call and ATM put with no further legs) collects more premium but carries theoretically unlimited risk on the call side and large downside risk on the put side. Adding the OTM long options converts the unlimited-risk straddle into a defined-loss structure, making it possible to know the worst-case outcome before entry.

The straddle calculator models the plain short straddle if you want to see how the unprotected version compares in terms of premium and breakevens.

Common Mistakes When Modeling an Iron Butterfly

Assuming the stock will pin the center strike

The maximum profit scenario requires the stock to close exactly at the short strike, which is the least likely single price outcome. When evaluating the structure, look at the full range of outcomes across the profit zone, not just the peak.

Ignoring the width of the wings

Maximum loss is directly tied to wing width. A wider wing means more protection but also a larger maximum loss if the stock moves far. Narrower wings reduce the max loss but also reduce the net credit collected, pushing the breakevens closer to the center strike.

Not accounting for early assignment risk

Short calls on dividend-paying stocks may be exercised early. If the short call is exercised, the position structure changes and the defined-risk profile may no longer apply. This is most relevant near ex-dividend dates.

Using the wrong expiration

Iron butterflies are typically shorter-dated because time decay (theta) works in favor of the short-premium structure. Longer expirations leave more time for the stock to move away from the center strike. Modeling the position across different expirations shows how net credit and breakeven range change.

Frequently Asked Questions

What is the maximum profit on an iron butterfly?

Maximum profit equals the net credit collected when the position is opened. It is achieved only when the underlying closes exactly at the center (short) strike at expiration. For example, if the net credit is $6.00 per share, the maximum profit is $600 per contract.

What is the maximum loss on an iron butterfly?

Maximum loss equals the wing width minus the net credit received. If the wing width is $10 and the net credit is $6, the maximum loss is $4.00 per share ($400 per contract). The loss is capped because the long options prevent further losses beyond the outer strikes.

How do you calculate the breakeven prices for an iron butterfly?

The upper breakeven equals the center strike plus the net credit. The lower breakeven equals the center strike minus the net credit. Using a $100 center strike and a $6.00 net credit, the breakevens are $106 and $94.

What is the difference between an iron butterfly and an iron condor?

In an iron butterfly, both short strikes are the same (at the money). In an iron condor, the short strikes are separated to create a wider profit range. The iron butterfly typically collects a higher credit but has a narrower zone where it profits at expiration.

Can the iron butterfly be closed before expiration?

Yes. Many traders close the position before expiration to lock in a portion of the profit or to limit losses if the position moves against them. Closing early involves buying back the short legs and selling the long legs. The net debit paid to close, subtracted from the original credit, determines the realized profit or loss.