True Strength Index (TSI)

Created by William Blau, the True Strength Index is a momentum oscillator that uses a series of exponential moving averages to depicts trends in price changes. [Discuss] 💬

chart for True Strength Index (TSI)

// C# usage syntax
IEnumerable<TsiResult> results =
  quotes.GetTsi(lookbackPeriods, smoothPeriods, signalPeriods);


lookbackPeriods int - Number of periods (N) for the first EMA. Must be greater than 0. Default is 25.

smoothPeriods int - Number of periods (M) for the second smoothing. Must be greater than 0. Default is 13.

signalPeriods int - Number of periods (S) in the TSI moving average. Must be greater than or equal to 0. Default is 7.

Historical quotes requirements

You must have at least N+M+100 periods of quotes to cover the convergence periods. Since this uses a two EMA smoothing techniques, we recommend you use at least N+M+250 data points prior to the intended usage date for better precision.

quotes is a collection of generic TQuote historical price quotes. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.



Convergence warning: The first N+M+250 periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.


Date DateTime - Date from evaluated TQuote

Tsi double - True Strength Index

Signal double - Signal line (EMA of TSI)


See Utilities and helpers for more information.


This indicator may be generated from any chain-enabled indicator or method.

// example
var results = quotes

Results can be further processed on Tsi with additional chain-enabled indicators.

// example
var results = quotes