Short Call Butterfly Calculator

Short Call Butterfly at a glance

How a short call butterfly works

The short call butterfly is the exact opposite of the long call butterfly. You sell the outer wings and buy the body, which brings in a modest credit because the two calls you sell on the outside are together worth more than the two at the money calls you buy. The trade is a bet that the stock will not stay where it is. Both risk and reward are capped, which makes it a defined risk way to be long volatility without paying a debit.

At expiration, the payoff is an upside down tent. If the stock is below the lower strike, every call expires worthless and you keep the credit. If it is above the upper strike, the two long calls exactly offset the two short calls and you again keep the credit. Between the outer strikes the position loses, with the worst result at the middle strike, where the loss equals the wing width minus the credit.

Before expiration, the short call butterfly is long gamma and long vega near the middle strike, so a sudden move or a jump in implied volatility helps, while quiet days cost time decay. The catch is that the profit is small relative to the risk, and much of it arrives only as expiration nears. A large early move often shows a smaller gain than the expiration chart suggests, because the outer short calls still carry time value until the final days.

Short Call Butterfly example with real numbers

With the stock at $100, implied volatility at 30%, a 4.1% risk free rate and no dividend, you would sell 1 95 call (32 days) at $6.77, buy 2 100 calls (32 days) at $3.73, sell 1 105 call (32 days) at $1.78. That is a net credit of $109. At expiration a maximum profit of $109 and a maximum loss of $391, with breakevens at $96.09 and $103.91. The lognormal chance of profit is 66%.

These are theoretical American option prices from the Bjerksund and Stensland model, not live quotes. Load any ticker in the short call butterfly calculator above to run the same math on real market prices.

When to use a short call butterfly

• You expect a breakout from a tight range but are unsure of the direction.
• Implied volatility is low and you expect it to rise, for example ahead of a catalyst.
• You want long volatility exposure with a credit at entry and a capped loss, rather than paying for a straddle.

Max profit, max loss and breakeven

Maximum profit

Net credit × 100. It is earned if the stock closes at or below the lower strike or at or above the upper strike at expiration.

Maximum loss

(Middle strike minus lower strike minus net credit) × 100. It occurs if the stock closes exactly at the middle strike at expiration.

Breakeven

Lower breakeven = lower strike plus net credit. Upper breakeven = upper strike minus net credit. The position profits outside these two prices at expiration.

Short Call Butterfly Greeks

• Delta: Close to zero at the middle strike. It turns negative as the stock falls toward the lower wing and positive as it rises toward the upper wing, so the position leans with the move.
• Gamma: Positive near the middle strike, so moves away from the center add profit at an increasing rate, and negative out near the short wings.
• Theta: Negative while the stock sits near the middle strike, because the two long at the money calls lose time value faster than the short wings.
• Vega: Positive near the center: rising implied volatility lifts the long body more than the short wings.

See the live numbers for your position in the Greeks tab of the calculator, or explore a single option in the options Greeks calculator.

Early exercise and assignment risk

The lower short call starts two strikes in the money, so it is exposed to early assignment from the first day, and the risk peaks the day before an ex dividend date if that call's time value is smaller than the dividend. If it is assigned, you are short 100 shares at the lower strike while still holding two long at the money calls and the short upper call. Exercising a long call to cover forfeits its remaining time value, so buying the shares back in the market and keeping the long calls is often the better choice.

If the stock rallies above the upper strike, both short calls are in the money and either can be assigned before a dividend, but your two long calls cover both, so the position stays balanced. Expiration brings pin risk at both wings: a close near the lower or upper strike leaves you unsure whether that short call will be assigned while your other legs settle cleanly. A close near the middle strike is the maximum loss zone and calls for closing early regardless. Exiting before the final hour avoids an unintended stock position.

The calculator's Early exercise risk tab flags short legs that are likely to be assigned. For a single option, use the early exercise calculator or read how early exercise and assignment work.

Pros and cons

How to manage a short call butterfly

• Open the trade close enough to the expected catalyst that time decay does not erode it while you wait.
• Close once the stock moves beyond a breakeven and most of the credit is showing, since the last part can take until expiration to arrive.
• Track ex dividend dates and close or roll the lower short call before one if its time value is below the dividend.
• If the stock stalls near the middle strike as expiration approaches, close to cap the loss rather than hoping for a late move.

Short Call Butterfly FAQ

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Educational tool, not financial advice. Calculations are theoretical and depend on your inputs; real fills, fees, early assignment and dividends can change results. Options involve risk and are not suitable for every investor.