Trading term

What is Delta?

Delta measures how much an option's price moves for each $1 change in the underlying. A delta of 0.60 means the option gains about $0.60 if the stock rises $1. It ranges from 0 to 1 for calls (0 to −1 for puts) and doubles as a rough probability the option finishes in the money.

Delta is the first and most-used of the option 'Greeks' — the sensitivities that describe how an option's price reacts to different forces. It answers the most basic question: if the stock moves, how much does my option move? A deep in-the-money call has a delta near 1 (it moves almost dollar-for-dollar with the stock, like owning shares); a far out-of-the-money call has a delta near 0 (it barely reacts). An at-the-money option sits around 0.50.

Delta has two other everyday uses. It's a rough gauge of the probability the option expires in the money — a 0.30-delta option has roughly a 30% chance of finishing ITM. And it tells you your effective share exposure: a 0.50-delta call behaves like owning 50 shares. Traders use delta to size positions, to build 'delta-neutral' hedges that cancel out directional risk, and to pick strikes by how stock-like (or lottery-like) they want the option to be.

Delta — the option's speed
at the money ≈ 0.50deep OTM (delta ≈ 0)deep ITM (delta ≈ 1)Delta of a call: 0 when deep out of the money → 1 when deep in the money

Delta is how much the option moves per $1 in the stock: near 0 deep out of the money, ~0.50 at the money, near 1 deep in the money. It doubles as a rough probability of finishing in the money.

For example

You buy a call with a delta of 0.40. The stock rises $2, so the option gains roughly $0.80 (0.40 × $2). That 0.40 delta also implies about a 40% chance the call finishes in the money, and exposure similar to owning 40 shares.

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Why it matters to you

Delta is the single most practical Greek: it tells you, in one number, how your option will react to the stock, roughly how likely it is to pay off, and how much share-equivalent exposure you carry. Almost every options decision — strike choice, position sizing, hedging — runs through delta.

⚠ Delta isn't fixed

Beginners treat delta as a constant, but it changes as the stock moves and time passes (that rate of change is gamma). An out-of-the-money option's delta can swing from 0.20 to 0.60 on a rally, so your exposure grows faster than you expect. Assuming a static delta underestimates how quickly an option's behaviour shifts.

Frequently asked questions

What does delta mean in options?

Delta is how much an option's price changes for each $1 move in the underlying. A 0.60 delta means the option gains about $0.60 per $1 rise in the stock. Calls have deltas from 0 to 1; puts from 0 to −1. It's the option's directional sensitivity.

Is delta the same as probability?

Roughly. An option's delta approximates the probability it finishes in the money — a 0.30-delta option has about a 30% chance of expiring ITM. It's a useful rule of thumb rather than an exact figure, but traders often use delta as a quick probability gauge when choosing strikes.

What is a delta-neutral position?

A delta-neutral position is built so the combined deltas of all its options and shares sum to zero, cancelling out directional risk. Small moves in the underlying don't change its value; the trader instead profits from other factors like time decay or volatility. Maintaining it requires rebalancing as delta shifts.

How does delta change?

Delta isn't fixed — it rises as an option moves in the money and falls as it moves out, and it shifts with time and volatility. The rate at which delta itself changes is called gamma. A deep-ITM option's delta approaches 1; a deep-OTM option's approaches 0.

Related terms

Call optionA call option is a contract giving the buyer the right — but not the obligation — to buy an asset at a fixed 'strike' price before a set expiry date. Call buyers are betting the price will rise; their risk is capped at the premium paid, while the potential profit is open-ended.Cash-secured putA cash-secured put is an options strategy where you sell a put option while setting aside enough cash to buy the stock if you're assigned. You collect the premium as income; in exchange, you agree to buy the stock at the strike if it falls there. It's a way to get paid to buy a stock you want at a lower price.Covered callA covered call is an options strategy where you own 100 shares of a stock and sell a call option against them. You collect the premium as income; in exchange, you cap your upside at the strike. It's a popular way to generate income on shares you're happy to hold or sell.Exercise & assignmentExercise is when an option holder uses their right to buy (call) or sell (put) the underlying at the strike; assignment is when the option seller is chosen to fulfil that obligation. Exercise is the buyer's action; assignment is what happens to the seller on the other side of it.
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