India VIX is built in five steps, from option prices to a thirty day annual volatility
India VIX is not the output of a model that someone fitted to the index. NSE takes the out of the money Nifty calls and puts from the near and the next month expiry and combines them into one figure for a thirty calendar day horizon. Each strike counts for its price times the gap to its neighbouring strikes, divided by the square of the strike, and the strips of the two expiries are blended by how far thirty days lies from each.
The steps run in order, and the chart lists them. First the forward is found, from the Nifty futures. Then the strip is added up for each expiry and turned into a variance. The two expiries are blended to thirty days, and the square root gives an annual volatility.
Two details matter for a reader. The first is missing quotes: where a strike has no quote, NSE fills the gap with a cubic spline. The second is the rate: a money market rate discounts the prices, and on a single day the rate moves the result only a little.
NSE computes the published figure from bid and ask quotes through the session. A replication built from end of day settlement prices will differ slightly, and the VIX replication tool shows that gap on dated sessions. The gap is expected.
Read the figure as a rough size of the move, not a forecast. Dividing the annual figure by the square root of twelve gives the one standard deviation move for a month. The index can close outside that band, and fat tails make the outside moves larger than the band suggests.
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