Concept
Percentile Rank
Percentile Rank, also known as quantile analysis, is a Statistics concept. The Library holds 6 implementations, each one a working definition you can pull into Quant.
Top Percentile Rank indicators
6 total
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What is Percentile Rank?
Percentile rank locates the current value of a series within its own recent history: it is the percentage of values in a lookback window that sit at or below the current one. A rank of 100 means nothing in the window exceeds it, a rank near 0 means almost everything does, and 50 sits at the median. Because the calculation uses order alone, it is distribution-free: one monster outlier in the window counts as just another observation above or below, and no normality assumption is required.
That robustness is why it appears wherever raw values are hard to compare. Options traders express implied volatility as a percentile of its past year, systems convert ATR or volume into a 0-100 regime dial, and machine-learning pipelines rank-transform features before combining them. The limitation is symmetrical: rank reports rarity within the chosen window, not direction or follow-through, and in a persistent trend a series can keep printing in its top decile for weeks.
How to calculate Percentile Rank
The nearest-rank calculation is counting, which is exactly why it is so robust.
- 1Collect the last N values of the series; this window is the reference distribution the current value is judged against.
- 2Count how many of those N values are less than or equal to the current value.
- 3Divide the count by N and multiply by 100 for a 0-100 reading. Implementations differ slightly (whether the current bar is counted in the window, nearest-rank versus interpolated definitions), which matters mainly on small windows.
How traders use it
- As adaptive overbought/oversold levels: instead of fixed oscillator thresholds, extremes are declared when a reading enters the top or bottom decile of its own history, so the bar for 'extreme' moves with the instrument's behavior.
- As a volatility regime switch: the volatility percentile of ATR or realized volatility decides which playbook applies, for example favoring range tactics in low percentiles and breakout tactics in high ones.
- As a participation filter: relative volume screens rank current volume against comparable history, so 'heavy' means heavy for that symbol at that time of day rather than an absolute number.
Percentile Rank vs related concepts
Z-score: A z-score measures distance from the mean in standard deviations, so it preserves magnitude and can exceed any bound; percentile rank uses order only and caps at 0 and 100. Ranks are more robust to outliers, z-scores more informative about how extreme an extreme actually is.
Min-max Scaling: Min-max scaling places the value proportionally between the window's low and high, so distances matter and one spike rescales everything. Percentile rank only counts how many values sit at or below. The options-market pair IV Rank (min-max) and IV Percentile (rank) shows how far apart the two can drift.
Stochastic Oscillator: %K is min-max scaling of the close within the recent high-low range, not a count of past values. A stochastic near 100 says price is at the top of its range; a percentile rank near 100 says almost no recent value was higher. Similar look, different arithmetic.
More Percentile Rank implementations
Related concepts · Normalization & distribution
Concept family
Statistics
45 concepts mapped · 37 in the Library
Percentile Rank FAQ
What is the difference between IV Rank and IV Percentile?
IV Rank is min-max scaling: where current implied volatility sits between its 52-week low and high. IV Percentile is percentile rank: the share of days over the same period with lower implied volatility. One volatility spike inflates the min-max range and depresses IV Rank for months afterward, while the percentile barely moves, so the two frequently disagree.
What lookback window should percentile rank use?
The window defines what 'unusual' means. Twenty bars measures short-term rarity; a year of data measures rarity within a broad regime, which is the convention in volatility work. Longer windows give stabler thresholds but adapt slowly after a structural shift, so match the window to how far back you believe conditions are still comparable.
Does a 100th percentile reading signal a reversal?
No. It only says the current value is the highest in the window, and strong trends print new highs repeatedly, re-marking 100 bar after bar. Rank supplies context about rarity; a tradable reversal case still needs structure, a level, or momentum evidence on top of it.
Build Percentile Rank your way.
Quant writes, tests, and refines it with you — then it runs on LuxAlgo charting or ports to TradingView.