Pine Script Percentile Function: ta.percentile_linear_interpolation Guide

Linear interpolation vs nearest rank percentile in v6

When evaluating historical distributions in TradingView Pine Script, choose whether the threshold may lie between observations or must be an observed value. Neither method guarantees a smooth series across successive bars.

Complete Pine Script v6 script: Rolling percentile price bands

With default inputs, the upper band is the 90th percentile of highs, the lower band is the 10th percentile of lows, and the middle band is the median of closes over 100 bars. These are three different samples, not an 80% confidence interval or a probability of future price containment. The current bar enters each sample; live bands and crossing markers can change until the bar closes. This indicator creates no orders or alerts.

//@version=6
indicator("Adaptive Percentile Bands [v6]", overlay = true)

// Input configuration
int lookback = input.int(100, "Lookback Period", minval = 10)
float upperPercentile = input.float(90.0, "Upper Percentile (%)", minval = 50.0, maxval = 100.0)
float lowerPercentile = input.float(10.0, "Lower Percentile (%)", minval = 0.0, maxval = 50.0)

// Calculate interpolated percentiles
float upperBand = ta.percentile_linear_interpolation(high, lookback, upperPercentile)
float lowerBand = ta.percentile_linear_interpolation(low, lookback, lowerPercentile)
float medianBand = ta.percentile_linear_interpolation(close, lookback, 50.0)

// Breakout signals
bool upperBreakout = ta.crossover(close, upperBand)
bool lowerBreakout = ta.crossunder(close, lowerBand)

// Visual plots
plot(upperBand, "Upper Percentile Band", color = color.red, linewidth = 2)
plot(medianBand, "50th Percentile (Median)", color = color.gray, linewidth = 1, style = plot.style_linebr)
plot(lowerBand, "Lower Percentile Band", color = color.green, linewidth = 2)

// Shape markers
plotshape(upperBreakout, "High Percentile Break", shape.triangleup, location.abovebar, color.red, size = size.tiny)
plotshape(lowerBreakout, "Low Percentile Break", shape.triangledown, location.belowbar, color.green, size = size.tiny)

// Dynamic channel fill
fill(plot(upperBand), plot(lowerBand), color = color.new(color.blue, 94), title = "Percentile Distribution Zone")

Practical applications of percentiles in trading systems

Percentiles express a threshold relative to the selected sample. The lookback and percentile remain modeling choices to test outside the data used to choose them:

• Volume filters: Compare volume with its rolling 95th-percentile threshold. Current-bar volume is incomplete until close; missing volume and tied observations affect interpretation.
• ATR context: A low percentile describes relatively low ATR within the sample. It does not establish the direction, timing, or size of a future breakout.
• Oscillator context: Rolling RSI percentiles identify values that are high or low relative to the chosen window. Such readings are not automatic reversal signals.

Common pitfalls when coding percentile functions

Watch for these calculation requirements in TradingView:

• Warmup and missing values: Check outputs with na() before acting on them. Do not convert an unavailable price threshold to zero with nz(); different percentile functions have different missing-value rules.
• Valid percentage range: Supplying a percentage below 0.0 or above 100.0 triggers a compilation or runtime error. Clamp parameter inputs using minval and maxval.
• Resource limits: Profile the actual script and chart history when increasing the lookback or number of calculations. There is no universal 500-bar performance cutoff.