# Swing Index

Plots Wilder's per-bar Swing Index (the signed measure of the true two-bar change built from both bars' opens and closes, scaled toward the -100/+100 extremes) with the limit-move factor T set automatically from the highest excursion over 252 bars or fixed manually. Dashed strong-swing levels sit at 50 and -50, and six alerts include validation of new 20-bar highs and lows.

- Indicator in the LuxAlgo Library, by LuxAlgo, published Apr 21, 2026.
- Access: free.
- Concepts: [Swing Index](https://www.luxalgo.com/library/concept/swing-index/) (primary)
- Open on Vela: https://vela.luxalgo.com/chart?pineScriptCodeId=me4s5buh6k07pvdi465v39lc
- Page: https://www.luxalgo.com/library/indicator/swing-index/

**Swing Index** computes Wilder's per-bar reading as published, then solves its one modern problem: the scale. The [Swing Index](https://www.luxalgo.com/library/concept/swing-index/) folds the close-to-close change, both bars' open-close positions and the dominant excursion from the prior close into one signed number, scaled by the limit move T that his era's futures exchanges provided and most modern markets do not. Auto mode in this first faithful build sets T to the highest excursion over a lookback, so the largest recent swing reads near the extremes; the line colors by sign over a gradient fill, framed by dashed strong-swing levels.

## How to Trade the Swing Index?

- **Sign**: above zero the net two-bar change is bullish, below zero bearish. Zero crossings carry alerts both ways.
- **Strong swings**: readings beyond the Strong Swing Levels mark single bars doing unusual directional work, with crossing alerts on each side.
- **Breakout validation**: a fresh high over the Breakout Lookback met by a strong positive reading fires Validated New High, Wilder's argument that the extreme is genuine rather than a spike; the mirrored check covers new lows.

Where no limit move exists T is a convention, so the sign and the relative size of readings do the work. The effective T is exposed in the data window.

## Swing Index Settings

- **Limit Move (T)** (default Auto (Highest Excursion)): how the scaling factor is set; Fixed Value uses the entered constant.
- **Fixed Limit Move Value** (default 1.0): T in price units for Fixed Value mode.
- **Auto Scaling Lookback** (default 252): bars inspected for the highest excursion in Auto mode.
- **Strong Swing Levels** (default 50 / -50): thresholds used by the strong-swing and validation alerts; tune them to the instrument.
- **Breakout Lookback** (default 20): window defining the new highs and lows the validation alerts test.

## Frequently Asked Questions

### When should I use the Accumulative Swing Index instead?

When you want the line Wilder actually drew on: the [Accumulative Swing Index](https://www.luxalgo.com/library/indicator/accumulative-swing-index/) totals these per-bar values into a synthetic price line for trendline and swing work. This build exposes the raw per-bar material.

### Why does my reading differ from another implementation's?

Almost always T. Without a real limit move every implementation picks its own scaling convention, and absolute readings only match when both use the same constant. Fixed Value mode lets you reproduce a known one.

### Are Auto-scaled readings comparable across symbols?

Comparable in spirit, not in value: each symbol is scaled by its own largest recent excursion. Treat the strong-swing levels as per-instrument conventions.

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Source: https://www.luxalgo.com/library/indicator/swing-index/ (LuxAlgo Library). Free to use with attribution: https://www.luxalgo.com/library/license/