Extra indicators
TSI: True Strength Index
A doubly smoothed momentum oscillator that shows the trend's strength with little noise.
The idea in plain words
The candle-to-candle change is smoothed twice with EMAs and divided by the equally smoothed size of the changes, giving a calm line between −100 and +100.
How it is calculated
Smooth the price change with EMA(25) then EMA(13); do the same with the absolute change; divide and multiply by 100. The signal line is an EMA(13) of TSI.
TSI = 100 × EMA(EMA(Δclose, 25), 13) ÷ EMA(EMA(|Δclose|, 25), 13)
Signal = EMA(TSI, 13)How to use it
- TSI crossing its signal line.
- Zero line: above it buyers dominate.
Drawing conclusions
- Readings beyond ±25 are often called strong; the exact levels vary by ticker.
Example
EURUSD daily: TSI crosses above its signal line at −18 after a long decline; a first sign that selling pressure is fading.
Prices in examples are illustrative.
Watch out for
- Double smoothing means late signals at sharp turns.
A little history
Developed by William Blau and published in 1991.
Educational content only. No indicator or pattern predicts the future, and nothing here is investment advice.