Nifty's 30 day implied volatility spiked once in the window and then came back to the lower part of its range
Open the NSE option chain and each traded strike has an IV figure. It is the volatility that makes the Black 76 price equal the settle price of that strike, with the future as the forward and the time to expiry in years. The at the money reading is the number people quote when they say the chain's IV.
IVP is a different measure. It does not come from one chain. It asks where today's IV sits in its own history: the share of past trading days on which the 30 day at the money IV was lower than today's. A high IVP means the option market is pricing more movement than it usually did across the series. A low IVP means the reverse.
The chart is the Nifty series that IVP is built from. The IV reached its high on 30 Mar 2026, and by 10 Jun 2026 it had come back to the lower part of the range. The series starts on 1 Jul 2025, so that window is about eleven months, not a full year. One spike like that sets the top of the scale, which is why rank and percentile can give very different readings on the same day.
IVP does not say whether an option is cheap or dear against the movement that follows. That needs realised volatility, covered in the question on historical against implied volatility. Also, a chain IV is for one expiry and one strike, while IVP uses a constant 30 day maturity, so the two numbers are measured on different bases.
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