Free Options Greeks Calculator
Calculate Delta, Gamma, Theta, Vega, and Rho for any options position. Understand how your options will behave with price moves, time decay, and volatility changes.
Try it now: Calculate Greeks for AAPL options with real-time data - no signup required!
Use Free Greeks Calculator →Understanding the Options Greeks
Delta (Δ) - Price Sensitivity
Delta measures how much an option's price changes when the stock price moves $1. It ranges from 0 to 1.00 for calls and 0 to -1.00 for puts.
Pro Tip: Delta also approximates probability of expiring ITM. A 0.30 delta call has ~30% chance of being in-the-money at expiration.
Gamma (Γ) - Delta Acceleration
Gamma measures how much delta changes when the stock moves $1. High gamma means your delta changes rapidly, creating acceleration in profits (or losses).
Pro Tip: Long gamma is great for trending moves (profits accelerate). Short gamma is dangerous - losses accelerate as stock moves against you.
Theta (Θ) - Time Decay
Theta measures how much value an option loses each day as time passes. Long options lose value (negative theta), short options gain value (positive theta).
Pro Tip: Theta accelerates in the final 30 days. If buying options, close before the final week to avoid extreme decay. If selling, target 30-45 DTE for optimal theta collection.
Vega (ν) - Volatility Sensitivity
Vega measures how much an option's price changes when implied volatility changes by 1 percentage point. Long options have positive vega, short options have negative vega.
Pro Tip: Buy options when IV is low (below 30th percentile), sell when IV is high (above 70th percentile). Vega is often more important than delta for options success.
Rho (ρ) - Interest Rate Sensitivity
Rho measures how much an option's price changes when the risk-free interest rate changes by 1 percentage point. Generally the least important Greek for most traders.
Pro Tip: Rho only matters for LEAPS (1+ year expiration). For options under 90 days, you can safely ignore rho.
How to Use Greeks in Your Trading
For Option Buyers
- Look for high delta if you want directional exposure (0.60-0.80 for calls)
- Buy when vega is positive and IV is low (below 30th percentile)
- Watch theta - close positions before final 2 weeks to avoid rapid decay
- High gamma is good for swing trades (profits accelerate)
For Option Sellers
- Sell when IV is high (above 70th percentile) for maximum vega profit
- Target 30-45 DTE for optimal theta decay collection
- Avoid high gamma positions (ATM short-dated) - too risky
- Sell OTM options (0.20-0.30 delta) for higher win rate
Frequently Asked Questions
Which Greek is most important?
It depends on your strategy. For option buyers before events, vega is most important (buy low IV). For theta sellers, theta and delta matter most. For short-term traders, gamma drives rapid P&L changes. Most professionals watch all Greeks simultaneously.
How often do Greeks change?
Greeks update constantly as stock price, IV, and time change. Delta and gamma change with every stock price tick. Theta decreases every day (accelerating near expiration). Vega changes with IV shifts. Our calculator updates Greeks in real-time every 15 milliseconds.
Can Greeks predict option prices perfectly?
No. Greeks give you the rate of change at a specific moment, but they change as conditions change. Think of delta as your speedometer - it tells you current speed, not where you'll be in an hour. Use Greeks to understand sensitivity and risk, not as guarantees.
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