Put Calendar Spread Calculator

By Yojana Mandon · Updated June 2026 · 2 min read · Risk disclaimer

A put calendar sells a near-term put and buys a longer-term put at the same strike, profiting from the faster decay of the front option. The put-based mirror of the call calendar — multi-expiration, defined risk.

⧉ Embed this free calculator on your site →

Key characteristics

• Max loss = net debit paid; profit peaks near the strike at front expiration.
• Benefits from rising implied volatility and time decay of the short leg.
• Uses puts instead of calls — often placed slightly below price for a neutral-to-soft view.
• Multi-expiration — modelled automatically here.

How a put calendar works

You sell a near-term put and buy a longer-term put at the same strike. The near option decays faster than the far one, so the spread profits from time passing while the stock sits near the strike — a tent-shaped payoff centred on that strike.

Because the two legs expire on different dates, the far put still holds time value when the near put expires, which is what creates the profit zone around the strike.

Risks and management

Maximum loss is the net debit paid, reached if the stock moves far from the strike in either direction or implied volatility falls. Like all calendars, it actually benefits from a rise in implied volatility, since the longer-dated leg gains more than the short one.

Choose the strike to match your bias: at the money for neutral, slightly below the price for a soft-bearish lean. Manage it by closing for a partial profit rather than holding for a perfect pin.

On the Greeks, the Put Calendar Spread is close to vega-neutral, so implied-volatility shifts have little net effect.

Managing the trade and common mistakes

Most experienced traders target a profit of 25–40% of the net debit paid and exit the entire spread before the short put expires. The sweet spot is when the underlying has drifted toward the short strike but implied volatility on the back-month put has stayed flat or risen — at that point the position is near its theoretical maximum value. If the trade moves against you early, a hard stop at roughly 50% of the debit limits damage; calendar spreads can erode quickly once the short put gains intrinsic value or front-month volatility collapses.

Rolling is the most common adjustment: when the short put is approaching expiration with the underlying still near your target strike, you close the short leg and sell the next monthly put at the same or nearby strike, collecting additional credit. Avoid rolling to a strike far from the current price — you are resetting your directional assumption and the new position may no longer behave like a calendar. Never let the short put expire in the money without actively managing it, because assignment on a cash-settled index put differs from assignment on a single-stock put, where you could be short shares over a weekend.

Beginners most often underestimate liquidity risk: put calendars on individual stocks can have wide bid–ask spreads on the back-month leg, so always use limit orders and price the spread as a single unit rather than legging in separately. A second common mistake is ignoring the volatility skew — if the back-month put carries significantly higher implied volatility than the front month, the apparent edge shrinks fast when vol mean-reverts. Finally, watch for earnings or dividend dates inside the spread window: an ex-dividend date can make early assignment on the short put rational for the counterparty, and an earnings event can crush or spike volatility in ways that overwhelm theta decay entirely.

Calculate it live

Use the free OptionProfit Put Calendar Spread calculator to load a live option chain, build the trade, and instantly see the payoff chart, breakevens, probability of profit, Greeks and a Monte Carlo simulation of outcomes.

Frequently asked questions

Educational use only. Quotes are delayed ~15 minutes and nothing here is financial advice. Options trading involves substantial risk of loss. Privacy Policy · Terms & Conditions.