Free · No Signup Required

Calendar Spread Calculator

Model your calendar spread before you place it. Enter your strike, front-month premium received, and back-month premium paid to instantly see net debit, max loss, and a full P&L diagram.

Net Debit Strategy Profits from Time Decay Defined Max Loss Interactive P&L Diagram
Black-Scholes-Merton pricing with dividend yield; American-style early exercise available below.

Underlying Asset

$
%
%
$

Strategy Template (optional, pre-fills legs below)

Option Legs

Implied volatility is solved automatically from the premium you enter (still editable). Legs with different expirations are supported (calendar spreads). Fetch a price above to pick strikes and premiums from the live option chain.

Free trading journal

See whether your calendar spreads are actually profitable over time

You just modeled this calendar spread’s payoff. The free options trading journal template (Excel and Google Sheets) logs every position so you can track your real win rate, average P&L, and trade history by strategy.

  • ✓Works with any broker, in Excel or Google Sheets
  • ✓Track win rate, average P&L, and trade history by strategy
  • ✓Free, no credit card needed

We’ll email you the free template. Unsubscribe anytime.

Getting Started

How to Use This Calculator

Three inputs are all you need. Results update instantly as you type.

1

Pull current market data (optional)

Type a ticker like AAPL and click Get Price. The calculator fills in the current stock price, dividend yield, and the risk-free rate from the 13-week T-bill, then loads the option chain so you can pick actual strikes and premiums.

2

Set up your calendar spread legs

The calendar spread legs are preloaded for you. Pick each strike, expiration, and premium straight from the option chain, or type your own numbers. The calculator works out implied volatility from the premium you enter, and you can still edit it.

3

Calculate and read the results

Click Calculate P&L to see max profit, max loss, breakeven, return on risk, and probability of profit, plus position Greeks: delta, gamma, theta, vega, and rho.

4

Stress test before you trade

Drag the view-date slider to see your P&L curve on any day before expiration, shift implied volatility up or down 50 points, and scan the price-by-date P&L table to see how the trade behaves across scenarios.

This calendar spread calculator prices each leg with your choice of an American-style binomial model (the default for US equity options) or European Black-Scholes-Merton, and accounts for dividend yield. You can set a per-contract commission, copy a shareable link to your exact setup, download the chart as a PNG, and switch to dark mode.

Strategy Breakdown

Understanding the Calendar Spread

Key numbers every calendar spread trader needs to know before entering the position.

Max Profit
Stock at Strike at Front-Month Expiry
Max profit is achieved when the stock closes right at the strike price at the short option’s expiration. The short option expires worthless and the long back-month option retains maximum time value, widening the spread to its peak value.
Max Loss
Net Debit Paid
Occurs when the stock moves far away from the strike in either direction by expiration, causing both options to lose time value and the spread to collapse toward zero. Your loss is capped at the net debit you paid to enter.
Breakeven
Two Points Flanking the Strike
Calendar spreads have an upper and lower breakeven. The exact prices depend on implied volatility and time remaining in the back-month option at expiration, so they are estimated rather than fixed at entry.

The calendar spread is a time decay strategy that exploits the difference in theta (time decay) between two options at the same strike but different expirations. Near-term options decay faster than longer-dated ones, especially as expiration approaches. By selling the fast-decaying front-month option and owning the slower-decaying back-month option, you benefit when time passes and the stock stays near your chosen strike.

Calendar spreads are ideally entered when implied volatility is low. Low IV means you pay less for the back-month option, reducing your net debit. If IV rises after entry, the back-month option gains more value than the short option loses, giving you an additional tailwind. The trade is sensitive to large moves in either direction, which is why many traders use them during low-volatility, range-bound periods in the market.

After the front-month option expires, you are left holding the back-month option outright. At that point, you can sell another near-term call or put to create a new calendar spread, continuing to collect premium and reduce your cost basis over multiple cycles.

Worked Example

Calendar Spread Example Trade

XYZ is trading at $100. You sell a 30-day $100 call for $2.00 and buy a 60-day $100 call for $4.00.

Position Summary
Stock Price$100.00
Strike Price (Both Legs)$100.00
Front-Month Premium Received (30-day)+$2.00 / share (+$200)
Back-Month Premium Paid (60-day)−$4.00 / share (−$400)
Net Debit−$2.00 / share (−$200)
Max Loss−$200 (net debit, if stock moves far from $100)
Best OutcomeStock at $100 at 30-day expiry (short call expires worthless)
After Front-Month ExpiryStill hold 30-day $100 call — can sell another front-month call
Breakeven RangeApproximately $95 – $105 (depends on IV at expiry)
Avoid these errors

Common calendar spread mistakes to avoid

Calendar spreads have a narrow profit window and more moving parts than most defined-risk trades. These are among the most common mistakes that lead to losses on this strategy.

Ignoring the IV relationship between legs

A calendar spread is a vega trade as much as a directional one. The back-month leg carries more vega than the front-month. If implied volatility drops after entry, the back-month loses more value than the short front-month gains from theta, even if the stock stays exactly where you need it. Enter in low-IV environments, where the spread benefits from any subsequent IV expansion.

Placing the spread across an earnings date

If a scheduled earnings announcement falls between your two expiration dates, the back-month prices in an earnings premium the front-month does not. When the announcement passes, that premium collapses and your back-month leg drops sharply regardless of the stock’s move. Unless you are trading the IV crush itself, avoid calendars that span a known catalyst date.

Picking a strike far from the current price

A calendar spread profits when the stock closes near your chosen strike at front-month expiry. The further the stock moves away from that strike before expiration, the faster the time-value differential between legs collapses. At-the-money or slightly out-of-the-money strikes give the strategy the widest profit window. Off-center strikes require a strong directional conviction to justify.

Having no plan for after front-month expiry

Once the short front leg expires worthless, you hold a naked long option. If the stock has drifted far from your strike, that remaining long may be deep out of the money with limited recovery potential. Decide before entering whether you will close the full spread before expiry, roll the short leg to the next month, or exit the back-month outright. Do not wait until expiry Friday to decide.

Waiting for a theoretical max profit that rarely arrives

Unlike a vertical spread, a calendar spread has no fixed dollar max profit. The peak spread value occurs only when the stock is pinned at your strike at front-month expiry with unchanged IV: a rare alignment. In practice, most traders exit at 25 to 50 percent of the net debit paid. Holding longer to squeeze out the last dollar of decay often results in giving the gains back as both legs deteriorate together.

Sizing as if the net debit is the only risk

The stated max loss on a calendar spread is the net debit paid, but a large fast move in either direction can drive the spread to near zero before expiry. A volatile stock can breach both sides of your profit window well before front-month expiry, leaving little time to adjust. Use the net debit as your actual risk figure and size accordingly. If you need a wider profit range on the same underlying, the iron condor calculator models a multi-leg alternative with defined breakevens on both sides.

All strategies

Explore other options strategy calculators

Each strategy has its own dedicated calculator with a full P&L breakdown, worked example, and FAQ.

Basic Strategies
Long Call Calculator →
Bullish. Defined risk, unlimited upside.
Short Call Calculator →
Bearish to neutral. Collect premium, unlimited theoretical risk.
Long Put Calculator →
Bearish. Defined risk, high reward potential.
Short Put Calculator →
Bullish to neutral. Sell a put for income.
Covered Call Calculator →
Generate income on stock you already own.
Cash-Secured Put Calculator →
Collect premium while waiting for a stock at your price.
Protective Put Calculator →
Insure 100 shares with a long put. Capped downside, open upside.
Vertical Spreads
Bull Call Spread Calculator →
Bullish. Defined risk and reward. Lower cost than a long call.
Bull Put Spread Calculator →
Bullish to neutral. Collect a net credit.
Bear Call Spread Calculator →
Bearish to neutral. Sell a call spread for a credit.
Bear Put Spread Calculator →
Bearish. Pay a debit to profit if the stock falls.
Option Spread Calculator →
Compare all vertical spread strategies side by side.
Neutral & Volatility
Iron Condor Calculator →
Neutral. Collect premium in a sideways market.
Iron Butterfly Calculator →
High-probability neutral trade centered at one strike.
Straddle Calculator →
Profit from a big move in either direction.
Strangle Calculator →
Like a straddle with wider strikes and lower cost.
Covered Strangle Calculator →
Stock plus short strangle for enhanced income.
Advanced & Multi-Leg
Butterfly Spread Calculator →
Low-cost trade that profits if the stock pins at your target.
Broken Wing Butterfly Calculator →
Asymmetric butterfly. Skew your risk to one side.
Jade Lizard Calculator →
Short put plus bear call spread. No upside risk.
Ratio Spread Calculator →
Buy fewer options than you sell to cut cost or collect credit.
Calendar Spread Calculator You are here
Sell short-dated, buy long-dated. Profit from time decay.
Diagonal Spread Calculator →
Like a calendar spread but with different strikes.
Double Diagonal Calculator →
Two diagonal spreads. Profits from a range-bound move.
Collar Options Calculator →
Protect a stock position with a defined floor and ceiling.
Poor Man’s Covered Call Calculator →
Capital-efficient covered call using a deep ITM LEAPS.
Synthetic Put Calculator →
Replicate a long put using short stock plus a long call.
Risk Reversal Calculator →
Sell a put to finance a call. Bullish, often near zero cost.

Free download

Download the free options trading journal

This calculator shows your P&L setup before the trade. Enter your email to get the free options trading journal template (Excel and Google Sheets).

  • Free trading journal template (Excel and Google Sheets)
  • Track win rate, average P&L, and trade history by strategy
  • Works with any broker. No app required.
No spam. Unsubscribe any time.
FAQ

Calendar Spread — Common Questions

A calendar spread (also called a time spread or horizontal spread) involves selling a near-term option and buying a longer-dated option at the same strike price. Both legs use the same underlying and strike but different expiration dates. The strategy profits from the difference in time decay rates: the short front-month option decays faster than the long back-month option. If the stock stays near the strike at the short option’s expiration, the spread value increases and you profit.
The maximum profit on a calendar spread is achieved when the stock closes right at the strike price at the front-month expiration. At that point, the short option expires worthless and the back-month option retains maximum time value, creating the largest spread between the two legs. The exact dollar amount depends on implied volatility and time remaining in the back-month option at expiration, which is why max profit is estimated rather than fixed. It is typically 50–100% of the net debit paid, and can exceed that in high-volatility environments.
The maximum loss on a calendar spread is the net debit paid to enter the position. This occurs when the stock moves far away from the strike price in either direction, causing both options to lose their time value and the spread to collapse toward zero. Because you are long the back-month option, the spread cannot go below zero, so your loss is strictly capped at what you paid. This makes the calendar spread a defined-risk strategy.
A calendar spread has two breakeven points — one above the strike and one below the strike. Unlike a single-expiration spread, the exact breakeven prices cannot be precisely calculated at entry because they depend on the time value remaining in the back-month option at expiration, which is driven by implied volatility. Higher implied volatility at expiration widens the profitable zone; lower volatility narrows it. As a rough guide, breakeven points are often 3–7% above and below the strike for a 30-day front-month expiration.
A calendar spread uses the same strike price for both the short and long option, differing only in expiration date. A diagonal spread uses different strike prices and different expiration dates. The poor man’s covered call is a well-known example of a diagonal spread, where the long leg is a deep in-the-money LEAPS and the short leg is an out-of-the-money near-term call. Calendar spreads profit most when the stock stays near the shared strike, while diagonal spreads can be structured with a directional bias depending on how the strikes are selected.

Related Calculators