Indicator · Pine Script v6 · On the chart

Kalman Filter (KALMAN)

by mihakralj

This indicator applies a one-dimensional Kalman filter to a chosen price source and plots the filtered series on the price chart.

View on GitHub

GitHub stars99on the repository
Pine versionv6current
Lines of code40
Settings3inputs
LicenceApache-2.0
Last update4 weeks ago27 Sep 2026

Add It to Your TradingView Chart

  1. 1Copy the scriptPress Copy script above, or the copy button on the code below.
  2. 2Open the Pine EditorOpen a TradingView chart and choose Pine Editor at the bottom of the screen.
  3. 3Paste over the templateCreate a new indicator, select all of the template text and paste. Press Save and give it a name.
  4. 4Add it to the chartPress Add to chart, then adjust the settings with the gear icon next to its name.

Source Code

40 lines of Pine Script v6 from lib/filters/kalman/kalman.pine, published under Apache-2.0. Keep the author's credit and licence lines when you reuse it.

kalman.pine
// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Kalman Filter (KALMAN)", "KALMAN", overlay=true)

//@function Applies a Kalman Filter to the input series
//@param src Input series (measurement)
//@param q Process noise covariance
//@param r Measurement noise covariance
//@returns Filtered series
//@optimized Uses Kalman filter with O(1) complexity per bar
kalman(series float src, simple float q, simple float r) =>
    if q <= 0.0 or r <= 0.0
        runtime.error("Process noise covariance (q) and measurement noise covariance (r) must be positive")
    var float x = na
    var float p = na
    float measurement = nz(src, 0.0)
    if bar_index == 0 or na(x)
        x := measurement
        p := 1.0
    float x_pred = x
    float p_pred = p + q
    float denom = p_pred + r
    float k_gain = denom == 0.0 ? 0.0 : p_pred / denom
    x := x_pred + k_gain * (measurement - x_pred)
    p := (1.0 - k_gain) * p_pred
    x

// ---------- Main loop ----------

// Inputs
i_source = input.source(close, "Source")
i_q = input.float(0.01, "Process Noise (Q)", minval=1e-9, step=0.01)
i_r = input.float(0.1, "Measurement Noise (R)", minval=1e-9, step=0.1)

// Calculation
kf_val = kalman(i_source, i_q, i_r)

// Plot
plot(kf_val, "KF", color=color.yellow, linewidth=2)

Overview

Process noise and measurement noise set how quickly the estimate follows new data versus how much it trusts the measurement. The function keeps a running state estimate and error covariance and updates both on every bar in constant time. It draws a single yellow line and does not generate trade signals or exits.

Details

Published by

mihakralj on GitHub

Type

Indicator, Pine Script v6

Draws

On the price chart

Category

Trend

Markets

Any symbol

Timeframes

Any timeframe

Risk Notes

No repainting, lookahead or stacked entries were found in its code or README. That says nothing about how well it works: test it first.

Topics

algorithmic-tradingcsharpdotnetpinescriptpythonquantitative-financesimdta-libtechnical-analysistechnical-indicators

Settings

The inputs you can change from the gear icon on the chart. Defaults are the author's.

SettingTypeDefaultVariable
Sourcesourceclosei_source
Process Noise (Q)float0.01i_q
Measurement Noise (R)float0.1i_r
Third-party code. ForexR did not write, test or endorse this script, and the summary above was generated automatically from its code and README. Indicators describe the past, and a strategy's backtest can look better than live trading, especially when a script repaints. Check it in the Strategy Tester and on a demo account before you rely on it.

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