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Calendar spread explained, outcome by outcome

A calendar spread sells one expiry and buys a later one at the same strike. You pay a small amount to own the difference, and you want the stock to sit still.

Options guide · 9-minute read · Updated 2026-10-29

What a calendar spread actually is

Two options. Same stock, same Strike price, two different expiry dates.

• You sell the nearer expiry and collect a premium.
• You buy the later expiry and pay a premium.

The later one always costs more, because it has more time left. So a calendar spread is always a Net debit — money leaves your account the day you open it. That debit is the most you can lose.

Nothing about it is a credit trade. If a broker's ticket shows a credit, you have the legs the wrong way round.

The map of what else lives out here is in option strategies beyond the wheel.

Why the near leg losing time value faster is the whole point

Both options have time value. Time value drains away, but it does not drain evenly. It leaves a near-dated option much faster per day than a long-dated one.

That is the engine. You are short the fast-draining option and long the slow-draining one. Every quiet day, the thing you owe shrinks faster than the thing you own.

Here is the same spread with a made-up stock sitting perfectly still at $50 (hypothetical, so the numbers stay clean):

Look at the two middle columns. Over those 30 days the near call lost $1.50 of value and the far call lost only $0.75. You were short the first and long the second, so the gap widened in your favour.

That gap is your profit. Theta is the name for the daily drain, and theta decay explains why it speeds up near the end.

A worked example (an illustration, not a trade idea)

Northwind Freight, a made-up company, trades at $50. It has been quiet for weeks.

• Sell the 30-day $50 call for $1.50 → collect $150
• Buy the 60-day $50 call for $2.50 → pay $250
• Net debit: $100. That is the most you can lose.

Three weeks later a rumour goes round that a bigger carrier wants to buy Northwind. The stock runs to $60.

At the near expiry:

• The $50 call you sold is $10 in the money. You buy it back for $1,000.
• The $50 call you own, with 30 days left, is worth $1,005 — ten dollars of real value plus almost no time value, because a deep in-the-money call has hardly any left.
• The spread is worth $5. You paid $100.

Result: −$95. The stock moved the way a call buyer dreams about, and the calendar lost almost everything.

That is not bad luck. It is how the structure works, and the table below shows it from both sides.

Every outcome at the near expiry

Same trade, same $100 debit. The far call always has 30 days left when the near one expires.

Read the last column top to bottom. There are two break-even points, around $48 and $52. Between them you make something. Outside them you lose.

• Most you can make: about $75, and only if the stock finishes right at $50.
• Most you can lose: the $100 debit.

So you are risking $100 to make about $75, and the window where you win is roughly four dollars wide on a fifty-dollar stock. Most explanations of calendars leave that part out.

The values away from $50 are estimates. The far call's price depends on how much the market still expects the stock to swing, which is why the next section matters.

Why a big move hurts either way

Down at $40, the far call is nearly worthless. The near call expiring worthless feels like a win, but you have nothing left to sell.

Up at $60, both calls are deep in the money. They are both worth roughly the same real value, so the difference between them collapses toward zero.

A calendar only has value when both options still have time value in them. That is true near the strike and almost nowhere else.

Two other things move the spread:

• Implied volatility. You own the later option, so you own more Vega than you are short. If the market calms down and expected swings shrink, the far call loses more than the near one and the spread shrinks with it.
• Early assignment. US stock options can be exercised early. If the near call you sold is assigned, you wake up short 100 shares with a long call sitting beside them. That is a margin position, not a spread. Closing it costs money, and the trade stops behaving the way this page describes.

What you need before you try one

A calendar is two legs, so most brokers put it a level above covered calls on their Options approval level ladder. You usually need a margin account, and many Canadian brokers will not allow multi-leg spreads inside a TFSA or RRSP at all — check your own broker's current options agreement before you plan a trade around it.

The cash needed is small: the debit plus fees. That is the appeal, and the trap. A $100 debit feels harmless, so people open ten of them and are suddenly short ten near-dated calls on a stock that can gap overnight.

Three habits that keep calendars honest:

1. Pick a quiet stock, not a cheap spread. A wide spread with a low debit usually means the market expects a move.
2. Check the chain for both expiries. A thin later month with wide Bid and ask quotes can eat the whole gain when you go to close.
3. Close before the near expiry. Holding the short leg into expiry day adds assignment risk for no extra reward.

A calendar also sits oddly beside the wheel strategy. The wheel wants to own shares, so a dip is a chance to buy. A calendar never owns anything, and a dip is just the loss.

Before you risk anything, put your own numbers in the options payoff calculator.

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