What Is Delta?
Delta measures how much an option's price changes for a $1 move in the underlying asset. A call option with a Delta of 0.60 gains $0.60 when the underlying rises by $1. Put options have negative Delta (they gain when the underlying falls). ATM options have a Delta near ±0.50; deep ITM options approach ±1.00; deep OTM options approach 0.
How Delta Works
Delta also approximates the probability of an option expiring in-the-money. A 0.30 Delta call has roughly a 30% chance of being ITM at expiration. This probability interpretation helps traders select strikes based on their conviction level. High Delta options behave more like the underlying asset; low Delta options are leveraged lottery tickets.
Why It Matters for Traders
Delta hedging — maintaining a Delta-neutral position by continuously adjusting the hedge ratio — is the foundation of professional options market making. In crypto, where the underlying can move 10%+ in hours, Delta hedging is both critical and challenging. Traders use Delta to precisely quantify their directional exposure at all times.