Option Greeks
The Greeks measure how an option's price reacts to changes: delta (underlying price), gamma (change in delta), theta (time), vega (volatility) and rho (interest rates).
An option's price moves for more reasons than the stock moving. Time passes, volatility shifts and rates change. The Greeks split those forces apart so you can see which one is driving your profit and loss — and which one could hurt you next.
- Category
- Derivatives
- Reading time
- 4 min
- Also called
- The Greeks, Options Greeks, Option sensitivities
- Updated
The Greeks in plain words
The Greeks measure the main forces that move an option's price.1
Delta shows how much the option price is expected to move for a $1 move in the stock; calls have a delta between 0 and 1 and puts between 0 and −1.1
Theta measures how much value the option loses per day as time passes.1 Vega measures sensitivity to Implied Volatility.1 See Options.
How to read the Greeks, step by step
Start with delta
Delta tells you roughly how much the option gains or loses for a $1 move in the underlying.2
Check gamma
Gamma tells you how fast delta itself changes when the underlying moves $1.1
Count the daily cost of time
Theta is the change in value for each day that passes, and it grows as expiration nears.1
Check volatility exposure
Vega shows how much the option's value changes for a one-point move in implied volatility.3
Look at rho for long-dated options
Rho shows the effect of a one-point change in interest rates; it matters most for long-dated options.1
Remember they interact
Each Greek describes one factor holding the others constant, so real price moves combine them.1
Worked examples
Example 1 — Delta on a call
About +$100You hold one call contract (100 shares) with a delta of 0.50. The stock rises $2.
| Change per share | 0.50 × $2 = $1.00 |
| Change per contract | $1.00 × 100 = $100 |
Delta estimates the option's price change for each $1 move in the stock.1 Because delta shifts as the stock moves, this is an estimate, not an exact figure.1
Example 2 — Theta over a week
About −$35Your option has a theta of −0.05 per day. Nothing else changes for 7 days.
| Daily loss per contract | 0.05 × 100 = $5 |
| Loss over 7 days | $5 × 7 = $35 |
Theta is the change in value for each day that passes, holding all else constant, and it gets larger near expiration.1
Example 3 — Vega and a volatility jump
About +$30Your option has a vega of 0.10. Implied volatility rises 3 points, the stock does not move.
| Change per share | 0.10 × 3 = $0.30 |
| Change per contract | $0.30 × 100 = $30 |
Vega measures how the option's value changes for a one-point change in implied volatility.3
The main Greeks at a glance
| Aspect | Measures sensitivity to | Typical sign for a bought call |
|---|---|---|
| Delta | $1 move in the underlying | Positive (0 to 1) |
| Gamma | Change in delta | Positive |
| Theta | One day passing | Negative |
| Vega | One-point change in implied volatility | Positive |
How traders use the Greeks
Sizing directional bets
Delta converts an option position into an equivalent number of shares of Exposure.
Hedging
Market makers and traders offset delta with shares to stay neutral — see Hedging.
Managing time decay
Option buyers watch theta to know what waiting costs them each day.
Trading volatility
Vega shows how much a position gains or loses if Volatility expectations change.
Advantages and disadvantages
Advantages
- Break an option's risk into separate, understandable parts.
- Let you compare very different option positions on one scale.
- Help you build hedges with a clear target.
- Show the cost of time before you trade.
Disadvantages
- They are estimates that change as markets move.
- Each Greek assumes other factors stay constant.
- They depend on a pricing model and its inputs.
- Large moves can make delta-only estimates badly wrong.
Going deeper
Read as far as you need. Each level builds on the one before it.
Delta first
Beginner
Delta is the single most useful Greek: it estimates how much the option moves for a $1 move in the stock.1
Gamma and theta near expiry
Intermediate
Gamma usually peaks for at-the-money options close to expiry.1 Theta also becomes larger as expiration nears, so short-dated at-the-money options can swing and decay fast.
Common mistakes
Treating delta as fixed
Forgetting that delta changes as the stock moves.
Ignoring theta
Holding short-dated options without counting daily decay.
Forgetting the multiplier
Reading Greeks per share and forgetting a contract is usually 100 shares.
Overlooking vega
Being right on direction but losing because implied volatility fell.
Check your understanding
Test yourself before moving on. Each answer comes with an explanation.
Key points to remember
- The Greeks split an option's price changes into separate drivers.
- Delta: underlying price; gamma: change in delta.
- Theta: time decay, which speeds up near expiry.
- Vega: implied volatility; rho: interest rates.
- They are estimates that interact and change constantly.
Frequently asked questions
Which Greek matters most?
Do the Greeks change?
Are Greeks the same for puts and calls?
Further learning
- Options
The contracts the Greeks describe.
- Implied Volatility
The input vega responds to.
- Hedging
How delta is used to offset risk.
- Volatility
Why price swings matter for options.
Sources
This article is written in our own words. The sources below support the specific facts, rules and figures marked with a number in the text. Links open the original publisher’s page.
- FINRA. Options (opens in a new tab) Checked .
- Options Industry Council (OCC). Delta (opens in a new tab) Checked .
- Options Industry Council (OCC). Vega (opens in a new tab) Checked .
Educational content, not financial advice. Examples use hypothetical prices and simplified costs; actual fees, margin rules and regulations vary by broker, market and country. We are not affiliated with any publisher linked above. Last reviewed . Report an error or request a source credit.