FTB-C000443 / Indicator

True Strength Index

True Strength Index is one hundred times double-smoothed close change divided by double-smoothed absolute close change.

Also known asTSI

Advanced Formula defined 1 linked topicPublished

Definitions

In plain terms

It retains momentum direction in the numerator and normalizes it by similarly smoothed movement magnitude.

Technical

The contract freezes long then short periods, EMA alpha and seeds, staging, first-ready index, zero denominator, missing data, and optional signal exclusion.

Scope

TSI is not RSI and a zero crossing is not guaranteed trend confirmation.

Formula

TSI = 100 * double-smoothed change / double-smoothed absolute change
LaTeX: TSI_t=100\frac{EMA_s(EMA_l(\Delta C))}{EMA_s(EMA_l(|\Delta C|))}
SymbolMeaningUnit
double-smoothed changesigned momentum after two EMA stagesprice
double-smoothed absolute changeabsolute momentum after two EMA stagesprice

Output unit: percent

Examples

  • A governed lesson calculates or identifies True Strength Index only after its inputs, window, state, scale, and edge cases are declared.

Common misconceptions

  • TSI is not RSI and a zero crossing is not guaranteed trend confirmation.

Concept relationships

Prerequisites

Related

Where this concept is used

Evidence and governance

  1. True Strength Index TA-Lib · first party technical publication

    Supports: preferred label, short definition, technical definition, formula

    Limits: Long/short ordering, EMA seeds, warm-up suppression, optional signal line, and zero denominator vary by implementation.

Reviewed by
fintech-builder-batch-008
Last reviewed
2026-07-29
Next review
2027-07-29
Record status
published