Delta is the most important of the Greeks and the most widely used. It measures how much an option's price (the premium) changes for each $1 move in the underlying stock. Understanding it turns your trading from guessing into measuring.
Delta range
- Call option: from 0 to +1.
- Put option: from 0 to −1.
- At the money (ATM): delta near 0.50 (or −0.50 for a Put).
Example: a delta of 0.60 means the option gains $0.60 when the stock rises by one dollar, which is $60 per contract because it represents 100 shares.
Delta as a probability of profit
Delta can be read roughly as the probability that an option expires in the money. A delta of 0.30 means about a 30% chance the contract finishes profitable. Option sellers use this to pick low-probability contracts and collect their premium.
Delta in hedging
If you hold 100 shares (delta = +100) and want to neutralize the risk, you buy a Put with a delta near −1 to offset the position. This is the basis of institutional Delta Hedging.
Practical summary
Pick a higher delta (0.70 or more) when you want behavior close to the stock with conviction in the direction, and a lower delta (around 0.30) for low-cost speculation, knowing the chance of success is lower.
