Options Academy
Butterfly Spreads 102: The Math (Break-evens & Max Profit)
With evenly spaced strikes, butterfly math is fast: debit, max profit, and break-evens in seconds.
The Core Formulas
When strikes are evenly spaced (e.g., 50/60/70), these formulas apply:
Net Investment: Net debit paid.
Max Profit: Strike spacing - Net debit.
Downside Break-even: Lowest strike + net debit.
Upside Break-even: Highest strike - net debit.
Profit Range Width: 2 x (strike spacing - net debit).
Quick Formula Check
You can sanity-check a butterfly in seconds:
1) If debit is half the strike spacing, max profit is small.
2) If debit is very small, the profit range is wide, but you likely have directional bias.
3) If debit approaches spacing, the trade is not worth it.
Debit = 3, Spacing = 10
Max Profit = 7
Debit = 5, Spacing = 10
Max Profit = 5
Debit = 8, Spacing = 10
Max Profit = 2
Rule of Thumb
Avoid debits near spacing
Plug in the Example
Spacing is 10 points. Net debit is 3 points. Lowest strike is 50. Highest strike is 70.
Net investment = 3 points = $300.
Max profit = 10 - 3 = $700.
Downside break-even = 50 + 3 = $53.
Upside break-even = 70 - 3 = $67.
Net Investment
$300
Max Profit
$700
Downside Break-even
$53
Upside Break-even
$67
Commissions & Real-World Pricing
Butterflies involve three strikes and four option contracts, so commissions matter.
Also, the net debit depends on real-time bid/ask prices, not closing prices. Small quote differences can materially change the debit.
If you can't get a low debit for a wide strike spacing, the risk/reward may be less attractive.
A quick sanity check: when net debit approaches the strike spacing, max profit collapses.
Risk/Reward Snapshot
Because the max loss equals the debit, a butterfly can show high percentage returns if the debit is small.
In the 50/60/70 example, you risk $300 to make $700 at the center.
That is a 133% return on capital at max profit, before commissions.
Max Loss
$300
Max Profit
$700
Max Profit / Risk
2.33x
Profit Range
$53 to $67
Key takeaways
- Evenly spaced strikes create a symmetric payoff with simple math.
- Max profit equals strike spacing minus net debit.
- Break-evens sit at low strike + debit and high strike - debit.
- Always incorporate commissions and bid/ask spreads when sizing the trade.
Series
Butterfly Spread Masterclass
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