What is the probability my option expires in the money based on its delta?

How this is calculated

• This calculator uses the absolute value of delta as an estimate of the probability the option finishes in the money at expiration. This is a shortcut many options traders use straight off the option chain, not a separate calculation.
• Delta is not actually a probability. It measures how much an option's price moves for a $1 move in the underlying stock. In the Black-Scholes model, delta corresponds to a value called N(d1), while the more precise probability of finishing in the money corresponds to a related but different value called N(d2). The two numbers are close for many typical, moderate-volatility setups, and drift further apart as volatility rises or time to expiration stretches out.
• Probability of expiring out of the money is shown as the simple complement: 100% minus the probability of expiring in the money.
• Delta changes as the stock price, time to expiration, and implied volatility change, so this result reflects a single snapshot from the number you entered, not a fixed forecast for the life of the option.
• Expiring in the money does not by itself mean the trade was profitable. That depends on the premium paid and where the stock lands relative to the break-even price.