Bull Put Spread Calculator
Use this free bull put spread calculator to model your credit spread before you place it. Enter your two put strikes and net credit received to instantly see max profit, max loss, breakeven price, and a full P&L diagram.
How to use the bull put spread calculator
Enter your two put strikes and net credit above and the calculator updates in real time. Here is what each input does.
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.
Set up your bull put spread legs
The bull put 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.
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.
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 bull put 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.
Understanding the bull put spread
A bull put spread is built by selling an out-of-the-money put and simultaneously buying a further out-of-the-money put at a lower strike. You collect a net credit upfront. The strategy profits when the stock stays flat, rises, or declines only slightly through expiration. Because you are selling the more expensive option and buying a cheaper one to cap your risk, the spread comes in as a credit.
Time decay is your friend with this strategy. Every day the stock stays above your short put strike, theta erodes the value of both options but benefits your net position since you are a net seller of premium. This is why many traders favor credit spreads over debit spreads when they want a high-probability trade rather than an aggressive directional bet.
Probability of profit advantage
Because you are selling a put below the current stock price, the short strike can be placed at a level where the probability of the stock closing above it at expiration is quite high. A $50 short put on a stock trading at $60 has a wide margin before it is in trouble. The trade-off is that the credit you collect is smaller relative to the risk, but the frequency of winning trades is higher than with a debit spread targeting the same move.
When to use a bull put spread
Bull put spreads work well when you are bullish to neutral on a stock and want to profit from time decay and a stable or rising price. They are effective in high implied volatility environments where you collect a larger credit, and are commonly used on stocks where you are comfortable owning the shares at the short put strike if the trade goes wrong. If the stock drops sharply, the long put limits your loss to the spread width minus the credit received, giving you a clearly defined worst-case outcome.
Bull put spread example with real numbers
Here is a worked example you can enter directly into the calculator above to see the full P&L diagram in action.
Trade setup: XYZ stock trading at $55.00
Common bull put spread mistakes to avoid
A bull put spread collects a credit up front and profits if the stock holds above the short strike, but selling for too little edge or losing track of assignment risk can turn a high-probability trade into an avoidable loss. These are the errors that show up most often.
1. Selling too close to the money just to collect more credit
Placing the short put closer to the current stock price raises the credit you collect, but it also raises the odds the stock trades through that strike before expiration. A bigger credit that comes with a much higher chance of assignment is not automatically the better trade. Compare the credit received to the probability of profit shown above, not just the dollar amount.
2. Misjudging max loss
Max loss on a bull put spread is the width between the strikes minus the credit received, not the credit itself. That full loss is realized if the stock closes below the long put strike at expiration. Check the max loss figure in the calculator above against the width of your strikes before sizing the position.
3. Selling when implied volatility is already low
Because you are net short premium in a bull put spread, the credit you collect depends on how rich the puts are when you enter. Selling after volatility has already dropped means taking on the same defined risk for a thinner credit, with less room to benefit if volatility contracts further. A bull put spread is generally a better sale when volatility is closer to its recent highs than its lows.
4. Overlooking assignment risk on the short put
As the short put moves in the money and its remaining time value shrinks, particularly in the final days before expiration, early assignment becomes more likely. Assignment means buying 100 shares per contract at the short strike, which the long put still offsets but only if you manage both legs together instead of letting one get assigned while the other sits open.
5. Holding to expiration instead of managing at a profit target
A credit spread does not have to run until expiration to be profitable. Closing the position once a majority of the credit has decayed away locks in most of the available gain while cutting the remaining tail-risk window well before the last few days, when gamma risk near the short strike is highest.
6. Picking the wrong structure for your view
A bull put spread profits mainly from time decay in a neutral-to-bullish setup, and the credit received caps how much you can make even if the stock rallies hard past the short strike. If your view is closer to “the stock will rise” than “the stock probably will not fall,” a debit structure like the bull call spread calculator can capture more of a genuine move higher, since it is not capped by a fixed credit. Match the structure to how confident you are in a real move versus just avoiding a decline.
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Bull put spread calculator FAQ
Common questions about the bull put spread strategy and how to use this calculator.
A bull put spread is a bullish to neutral credit spread where you sell a put at a higher strike and buy a put at a lower strike on the same stock with the same expiration. You collect a net credit upfront. The trade profits if the stock stays at or above the short put strike through expiration, causing both puts to expire worthless so you keep the full credit. Your risk is capped by the long put you bought.
The maximum profit is the net credit received multiplied by 100 shares per contract. Using the example above, that is $150. You achieve max profit when the stock closes at or above the short put strike ($50) at expiration. Time decay accelerates this outcome as expiration approaches, especially in the final weeks of the trade when theta is highest.
The maximum loss is the spread width minus the net credit received, multiplied by 100. For a $5-wide spread with $1.50 in credit, max loss is $350 per contract. This occurs if the stock closes at or below the long put strike ($45 in the example) at expiration. The long put you bought prevents any further loss beyond the spread width, no matter how far the stock falls below that level.
The breakeven is the short put strike minus the net credit received. With a $50 short put and $1.50 in net credit, the breakeven is $48.50. If the stock closes exactly at $48.50 at expiration, the position breaks even. Above $48.50, the trade is profitable. Below $48.50, the loss grows until the stock reaches the long put strike ($45), at which point the maximum loss is reached.
Yes, a bull put spread and a short put spread refer to the same strategy. Both names describe the same trade: selling a higher-strike put and buying a lower-strike put to collect a net credit. The term “bull put spread” emphasizes the bullish directional bias, while “short put spread” describes the structure of the trade. You may also hear it called a put credit spread, which highlights that it brings in a credit when opened. All three terms mean the same thing.
This calculator is for educational and informational purposes only. Options trading involves substantial risk and is not suitable for all investors. Past performance is not indicative of future results. Always consult a licensed financial professional before making investment decisions.