IV Rank vs IV Percentile: Which Is Better?

If you sell options, IV percentile is the better main filter, and IV rank is a useful second look.

Percentile answers the question you actually have: is implied volatility higher than usual for this ticker? Rank answers a narrower one: how close is today to the single highest and lowest reading in the lookback window?

I built the IV history behind the options screener on this site, so I checked how often the two disagree. With the latest readings as of 23 September 2026, across 183 tickers with enough history, the median gap between IV rank and IV percentile was 13 points. On 62 tickers the gap was over 20 points. On 49 tickers one metric was 50 or above while the other was below.

What each metric measures

IV rank places today's IV inside the range of the lookback window:

IV Rank = (Current IV − Lowest IV) / (Highest IV − Lowest IV) × 100

If IV ranged from 20% to 60% over the year and it's 40% today, the rank is 50. Only three numbers matter: today, the low, and the high.

IV percentile counts days instead:

IV Percentile = (days with IV ≤ today's IV) / (days in the window) × 100

A percentile of 70 means IV was at or below today's level on 70% of the days in the window. Every day counts the same.

	IV rank	IV percentile
Uses	Today, the lowest and the highest reading	Every reading in the window
One big spike	Pulls the rank down for as long as it's in the window	Moves it by one day's worth
Question it answers	How close is today to the extremes?	How unusual is today?
Scale	0–100	0–100

Why rank reads lower on most tickers

Volatility doesn't spread evenly between its low and its high. It sits in a band most of the time and jumps occasionally: an earnings report, a sell-off, a news day. One of those jumps sets the top of the rank formula for as long as it stays in the window.

On those same readings, IV rank was below IV percentile on 128 of the 183 tickers. The median rank was 27, the median percentile 40.

If you use "IV rank above 50" as a sell filter, that gap matters:

Filter (latest readings as of 23 Sep 2026, 183 tickers)	Tickers passing
IV rank ≥ 50	23
IV percentile ≥ 50	72
Both ≥ 50	23

Every ticker that passed the rank filter also passed the percentile filter. The reverse wasn't true: 49 tickers had IV at or above most days in their window and still showed a rank below 50.

Three real examples

All numbers are from our IV history, latest readings as of 23 September 2026 (dated 22 September for these three).

JPM: rank below 50, percentile well above. At-the-money IV was 25.3%, at or above 65% of the readings in the window, so the IV percentile was 65. IV spiked in October 2025, and that one stretch keeps the top of the range high, so the rank was 29. A seller reading only the rank would call this cheap.

COST: the same pattern. IV was 23.5%, rank 37, percentile 79. The top of its range comes from a spike to 35.2% on 10 December 2025. On 79% of the days in the window COST's IV was at or below today's level. The rank puts it closer to the middle.

SPY: the two agree. IV was 11.6%, rank 19, percentile 22. Both say options on SPY were cheap for SPY that week. When the two metrics land close together like this, it doesn't matter much which one you read.

Which one to use

For premium selling (covered calls, cash-secured puts, credit spreads, iron condors):

1. Filter on IV percentile. Above 50 means IV is higher than on most days in the lookback window, so the premium is richer than usual for that ticker.
2. Read IV rank next to it. When rank sits far below percentile, a spike is in the window. The trade can still be fine, but you now know the ticker had one big move this year, which matters when you pick strikes.
3. Check what caused the spike. If it was earnings, check when the next report is. A percentile of 90 the week before earnings says more about the event than about the stock.

For buying options (long straddles, calendars), the same logic runs the other way. A low percentile says options are cheaper than usual. A low rank on its own might only mean the past year had one very volatile stretch.

Limits worth knowing

• Lookback. Both metrics depend on the window. Ours uses up to 252 stored daily readings per ticker. Our history for the tickers in this article starts in July 2025, so the window reaches back about 14 months rather than exactly one year.
• Which IV. Our readings are at-the-money IV on the nearest standard monthly expiration at least a week out, backed out of real option prices. Front-month IV jumps around earnings, so earnings spikes show up in the window.
• Absolute level. A percentile of 90 on a ticker with 12% IV is still 12% IV. Look at the raw number too.
• Skew. Neither metric says anything about put skew or the term structure. They describe one point on the volatility surface.

The badge above is live and the numbers in this article are dated, so they won't match exactly. The screener's percentile also still counts the older expiration-week readings I excluded here, so it can differ on some tickers.

How I got these numbers

I store one at-the-money IV reading per ticker per trading day, for about 300 tickers. For this article I took every ticker with a reading from 18 September 2026 or later and at least 200 readings in its window, which left 183. Rank and percentile use the same window.

Before September 2026, the ingest priced the nearest monthly contract even in the week it expired. Those readings run 13–26% too high, and on expiration day far too low. I excluded that week before every monthly expiration for the affected data source. New readings use a contract at least a week out, so the problem doesn't recur.

IV percentile is the better default for a seller. Rank is still worth reading next to it, because a big gap between the two is the quickest sign that a ticker had one large volatility event in the past year.

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