spreadsMedium RiskNeutral

Calendar Spread

Sell a near-term option and buy a longer-term option at the same strike.

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What is a Calendar Spread?

A calendar spread (also called a time spread or horizontal spread) involves selling a short-dated option and buying a longer-dated option at the same strike price. The trade profits from the difference in time decay rates between the two expirations: near-term options decay faster than longer-dated ones, so the short option loses value more quickly than the long option. The ideal outcome is for the stock to stay near the strike at the front-month expiration — the short option expires worthless (or close to it) while the long option retains most of its value, having decayed more slowly. Calendar spreads are unique in that they can be replayed: after the front-month expires, you sell another near-term option for the following month, effectively running a repeating income strategy on the long option you hold.

When to use it

Calendar spreads work best when you expect the stock to remain near the strike price and when IV is relatively low at entry (so the back-month option is cheaper). They are also used as a way to position for an IV spike — if you enter a calendar when IV is low and IV rises before the front-month expiration, both legs gain value but the long (back-month) gains more, making the spread profitable. A common use case is buying a calendar one or two weeks before earnings: if the stock stays near the strike after the announcement, the front-month collapses from IV crush while the back-month holds more value. Avoid calendars when the term structure is flat or inverted (back-month IV higher than front) — the economics deteriorate significantly.

Structure

Sell 1 near-term option (call or put) at a specific strike and buy 1 further-dated option at the same strike. The two legs differ only in expiration, not strike. Most traders use calls for a neutral-to-bullish bias or puts for a neutral-to-bearish bias, though a perfectly ATM calendar is fully neutral. The net cost is a debit — the long option costs more than the short option generates.

Key Metrics

Max Profit
Variable — not fixed at entry. Maximum profit is realized when the stock is exactly at the strike at the front-month expiration, in which case the short call expires nearly worthless while the long call retains its full time value. The exact profit depends on the implied volatility of the back-month option at that point. Backtests typically show maximum profit of 20–50% of the net debit paid in a single cycle.
Max Loss
The net debit paid to enter the spread. This is lost if the stock makes a large move in either direction — both options become intrinsically valued and the time-value differential that drives the trade's profit collapses. The maximum loss scenario is the stock gapping sharply far away from the strike before expiration.
Breakeven
Two breakevens — one above the strike and one below — defining a range within which the trade is profitable at expiration. The exact breakevens depend on the IV of the back-month option at expiration and cannot be precisely calculated at entry. A wider IV differential between the legs creates a wider profitable range.
Greeks Profile
Theta is positive — the near-term option decays faster, so time passage benefits the spread (as long as the stock stays near the strike). Vega is net positive and importantly asymmetric: the long back-month option has higher vega than the short front-month, so a rise in IV (especially in the back month) increases the spread's value. Delta is near zero if the calendar is placed ATM, but shifts if the stock moves away from the strike. Gamma is negative — sharp moves in either direction hurt the position.

Tips & Best Practices

  • 1Place the calendar at a price level where you expect the stock to consolidate — the trade requires the stock to stay in a range.
  • 2An IV of 20–30% for the back-month option is typically a good entry range — avoid entering when back-month IV is very high.
  • 3The front-month expiration is the key date — evaluate the position there and decide whether to take profits or sell another near-term option.
  • 4Calendars placed just before earnings can capture the pre-earnings IV rise in the back month while the front month collapses post-announcement.
  • 5Use calls for calendars in a mildly bullish environment and puts for mildly bearish — the ATM calendar is fully neutral.
  • 6Do not let the front-month option approach expiration as a short position without a plan — the gamma risk accelerates in the final week.
  • 7Close or adjust the calendar if the stock moves more than 5–8% away from the strike — the trade's probability has shifted significantly.
  • 8Manage the back-month option: if it is still valuable after the front-month expires, you can sell the next cycle's short option against it.

See it in action

Model a Calendar Spread with a real ticker. See the P&L chart, heatmap, and exact breakevens.

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