# What Is a Calendar Spread? Time Decay & Volatility Source: https://theoptionsbench.com/what-is-a-calendar-spread/ > Plain-text mirror for AI/LLM ingestion. Canonical HTML page: https://theoptionsbench.com/what-is-a-calendar-spread/ --- Updated 30 May 2026 · by Theo Chen A calendar spread sells a near-dated option and buys a longer-dated one at the **same strike**, both calls or both puts. You pay a small net debit and profit from the near leg decaying faster than the far leg while the stock sits near the strike. It is a bet on **time and volatility**, not direction. Want your net debit, the estimated profit peak and both breakevens? Enter the two expirations, the strike and the premiums and the calculator models the position at the near expiry. Open the Calendar Spread Calculator -> ## How is a calendar spread built? Two options on the same stock and the same strike, but different expirations: - Sell the near-dated option (the short leg). It decays fastest and is the engine of the trade. - Buy the longer-dated option (the long leg) at the same strike. It costs more, so the position opens for a net debit - the most you can lose. Calls or puts both work; at the same strike the payoff shape is nearly identical. The position is market-neutral around the strike and benefits from the stock standing still. ## Why is it a time and volatility trade? Two forces drive the profit. First, time decay: the near option loses value faster than the far one, so the gap between them widens in your favour as the near expiry approaches - as long as the stock stays near the strike. Second, **volatility**: the position is long vega, so rising implied volatility on the back-month option helps and falling volatility hurts. That second force is why the profit at expiry is an estimate, not a fixed number like a vertical spread. ## Max profit, max loss and breakevens - Max loss = the net debit you paid × 100. Both legs are options you hold, so you cannot lose more than the cost to open. - Max profit ≈ reached if the stock finishes at the strike at the near expiry - the leftover value of the long leg there, minus the debit. It is an estimate because it depends on the long leg's implied volatility at that point. - Breakevens = one below and one above the strike. Outside that band the position loses; the further the stock runs from the strike, the more of the debit you give back. ## Calendar vs diagonal spread A plain calendar uses the **same strike** for both legs, so it is direction-neutral. A **diagonal spread** uses **different strikes** as well as different expirations - a calendar tilted in a direction, adding a directional view on top of the time-decay edge. The poor man's covered call is the best-known diagonal: a long-dated in-the-money call standing in for stock, with shorter calls sold against it. (The calculator here models the same-strike calendar.) ## A worked example With the stock at $100, you sell the 30-day $100 call for $2.50 and buy the 60-day $100 call for $3.70 - a net debit of $1.20, or **$120**, which is your maximum loss. If the stock is still near $100 at the 30-day expiry, the call you sold expires near-worthless while your 60-day call still holds roughly $2.40 of value - so the spread is worth about $2.40, nearly double the $1.20 you paid. If the stock instead races to $130 or sinks to $80, both calls move together and you give back most of the debit. ## When a calendar spread makes sense Use a calendar when you expect a stock to sit near a price through the near expiration, ideally when near-term implied volatility is rich relative to the back month. It is a cheap, defined-risk way to sell time decay. Check whether volatility is high or low first with the IV Rank Calculator, and judge how far the stock might travel with the Expected Move Calculator. The bottom line A calendar spread profits from the near-dated option you sold decaying faster than the longer-dated one you own - it needs the stock to sit near the strike and is long volatility, so a big move in either direction works against it. ## Frequently asked questions What is a calendar spread? A calendar spread (also called a horizontal or time spread) sells a near-dated option and buys a longer-dated option at the same strike - both calls or both puts. You pay a net debit because the longer-dated option costs more. It profits when the stock sits near the strike at the near expiration: the option you sold decays to near-zero while the one you own keeps most of its time value. How does a calendar spread make money? From the difference in time decay between the two legs. The near-dated short option loses value (theta) faster than the longer-dated long option, so if the stock stays near the strike the gap between them widens in your favour. It is also long volatility - a rise in implied volatility on the back-month option helps, and a drop hurts. What is the max profit and max loss on a calendar spread? Maximum loss is the net debit you paid to open - and only that, because both legs are options you control. Maximum profit is reached if the stock finishes right at the strike at the near expiration; it equals the remaining value of the long leg there minus the debit. Unlike a vertical spread, that peak is an estimate, since it depends on the long leg's implied volatility at the near expiry. What is the difference between a calendar spread and a diagonal spread? A calendar spread uses the same strike for both legs. A diagonal spread uses different strikes and different expirations - it is a calendar tilted in a direction, so it carries a directional bias on top of the time-decay edge. The poor man's covered call is a well-known long-dated diagonal. The calculator on this site models the same-strike calendar. When should you use a calendar spread? When you expect a stock to sit near a chosen price through the near expiration, and ideally when near-term implied volatility is high relative to the back month (so the option you sell is richer). It is a low-cost, defined-risk way to sell time decay. It works against you if the stock makes a big move away from the strike in either direction. ## Related questions - What is a diagonal spread, the directional version? - How does a poor man's covered call use a LEAPS? - How does theta decay actually work? - What is theta in options?