IV Rank

IV Rank is a way of measuring whether an option's implied volatility (IV) is currently high or low compared to its own recent history. Implied volatility is the market's estimate of how much a stock or asset is likely to move, baked into the price of its options — higher IV generally means more expensive options.

IV Rank puts today's IV reading on a scale of 0 to 100 based on where it falls between the highest and lowest IV that underlying has seen over a chosen lookback period, commonly the past year. An IV Rank of 0 means current IV is at its lowest point of that period; an IV Rank of 100 means it's at its highest point. So an IV Rank of 80 says today's implied volatility is near the top of its one-year range, while an IV Rank of 15 says it's near the bottom.

The nuance that trips people up is that IV Rank is relative, not absolute. A stock that always has wild implied volatility might show an IV Rank of 20 while its IV is still numerically higher than a sleepy stock's IV Rank of 90. IV Rank tells you where volatility sits relative to that specific underlying's own past, not how volatile it is compared to other stocks. People also sometimes confuse it with IV Percentile, a related but different calculation that counts the percentage of days IV was below the current level, rather than measuring position between a high and low.

Because the lookback window and exact formula can vary slightly between brokers and platforms, the number you see for the same stock can differ from one screen to another.