The at the money call has a delta near one half and rises toward one as the future moves above its strike
Delta is the first of the Greeks, and it answers one question: if the future moves one point, how much does this option's premium move? A call's delta runs from zero to one, and a put's from minus one to zero. The figure is per unit of the underlying, so one lot of 65 units multiplies it by 65.
On the 10 Jun 2026 chain, the at the money Nifty call for the 30 Jun expiry had a delta near one half. Deep in the money it moves close to one for one with the future, and far out of the money it barely moves. The chart draws that curve against the level of the future, with twenty, ten and two days left, and the curve steepens as expiry nears.
Delta is also a hedge ratio. A short call with a delta of one half is offset, in quantity terms, by holding half a future for each call, which is why desks talk about delta neutral books. The hedge holds only at the moment it is set, because delta changes with the future, with time and with volatility. The delta hedging page covers the rebalancing.
A put's delta is close to the call's delta minus one (the gap is a small discount factor), which is why a long put and a long future move in opposite directions. Delta is a model output from the price and the volatility. It is often read as the chance of expiring in the money, which is a rough shortcut and not the definition.
Before you trade. Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. Read the SEBI study