Put Calendar Spread Options Strategy Guide
By OptionClaws, VirWare LLC · Updated 2026-08-23
A put calendar spread sells a put in a near expiration and buys a put at the same strike in a later expiration, for a net debit. The near put decays faster, so the spread widens if the stock is near the strike when the front put expires. Placed at the money it is a neutral time-decay trade; placed below the stock, where puts are usually struck, it adds a mild bearish tilt, paying best if the stock drifts down to the strike and stalls. Like its call counterpart it is long back-month volatility and short front-month volatility.
Key takeaways
- Sell a near-term put and buy a longer-dated put at the same strike for a net debit
- Profits most if the stock is at the strike when the front put expires
- Max loss is the debit; profit is bounded by the back put's value at the front expiry
- Struck below the stock, it is a time-decay trade that pays best on a controlled dip
When it makes sense
- You expect a drift down to a support level, then consolidation, through the front expiration
- Front-month put implied volatility is elevated relative to the back month
- You want a defined-loss, positive-theta position with downside bias
- You want to own longer-dated downside protection and finance part of it with near-term puts
How it works
Sell one put expiring in about 30 days and buy one put at the same strike expiring in 60 to 90 days, typically at a strike a few percent below the stock. The debit is the maximum loss. At the front expiration, with the stock at the strike, the short put expires worthless and the long put retains its time value, worth more than the original debit. If the stock is far above the strike both puts are nearly worthless; far below, both are deep in the money and worth nearly the same, so the spread collapses either way. Breakevens depend on the back put's remaining value and come from a model, not a formula.
Risk and reward
Maximum loss: the debit, when the stock is far from the strike at the front expiration. Maximum profit: at the strike at the front expiry, equal to the back put's value then minus the debit, commonly 20 to 60% of the debit for a 30/60-day spread. The short put is covered by the long put at the same strike, so margin is the debit only. Rising implied volatility on a sell-off helps the back put more than it hurts the front, as long as the stock has not blown through the strike.
Greeks and volatility
Net delta is slightly negative when the strike is below the stock and approaches zero as the stock reaches the strike. Theta is positive near the strike. Vega is positive net: long the back month, short the front. Because put implied volatility rises as the stock falls, a moderate decline toward the strike helps twice, through delta and vega. Gamma turns sharply negative in the final days before the front expiration if the stock is at the strike.
Managing the trade
Close the spread just before the front expiration to capture the widening, or let the short put expire and either keep the long put as protection or sell a new front-month put against it. If the stock falls through the strike, the short put can be assigned early once it is deep in the money with little time value; you would be long 100 shares against a long put, a fully hedged position you can unwind by exercising the long put or selling the shares. An earnings date between the two expirations belongs to the back put only; factor it in.
Worked example
Stock at $100. Sell the 30-day $95 put for $1.40 and buy the 60-day $95 put for $2.40, a $1.00 debit ($100). At the front expiration with the stock at $95 the short put expires worthless and the long put, now a 30-day at-the-money put, is worth about $2.60: the spread sells for $260, a $160 profit. With the stock at $104 the long put is worth about $0.70 and the short put is worthless, a $30 loss. With the stock at $80 both puts are worth about $15.00 and the spread is near zero, a loss of almost the full $100.
What to screen for
Screen put calendars by debit relative to the strike, the front-minus-back implied volatility gap, the strike's distance below the stock in percent or ATRs, and days to expiration in both months. Check for earnings between the expirations and require open interest in the back month, where put liquidity can thin out below the money.
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Frequently asked questions
- What is the difference between a put calendar and a call calendar?
- At the same strike the payoffs are nearly identical. Put calendars are the natural choice for strikes below the stock, because the short put is then out of the money and assignment is unlikely; call calendars suit strikes above it.
- What is the maximum loss on a put calendar?
- The debit paid, if the stock is far above or far below the strike at the front expiration.
- Does a put calendar protect against a crash?
- Only partially. In a crash both puts go deep in the money and converge in value, so the spread's profit shrinks back toward zero. It pays best on a controlled decline to the strike, not a collapse through it.
- Can the short put be assigned early?
- Yes, if it is deep in the money with little time value left. You would then own 100 shares hedged by the long put, which you can exercise or sell to unwind.
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Last updated 2026-08-23. Educational content, not investment advice. Options involve substantial risk and are not suitable for every investor. See our Terms of Service.