What it does
The True Strength Index (TSI) measures momentum by smoothing bar-to-bar price changes twice, then scaling the result between −100 and +100. It is drawn as a blue line with an orange signal line, plus reference levels at +25, 0 and −25.
Arrows mark closed bars where TSI crosses its signal line. An optional filter keeps only crosses that happen beyond the ±25 levels.
How it works
- Momentum m = close − previous close.
- Smooth m with an EMA of 25 bars, then smooth the result with an EMA of 13 bars.
- Do the same with the absolute value |m|.
- TSI = 100 × double-smoothed m ÷ double-smoothed |m|.
- Signal = EMA(7) of TSI.
- Bullish cross: TSI moves above the signal line after being at or below it on the previous bar. Bearish cross: the reverse. With the zone filter on, a bullish cross must happen below −25 and a bearish cross above +25.
Each EMA uses k = 2 ÷ (length + 1).
How to use it
- Above zero, the smoothed momentum is positive; below zero it is negative. Zero-line crosses are a slower, broader read on direction.
- Signal-line crosses are faster. In an uptrend, bullish crosses after a dip are the ones trend followers watch; bearish crosses are often just pauses.
- Readings beyond ±25 show stretched momentum. The zone filter is useful if you only want reversal-style crosses from those extremes.
- TSI also lends itself to divergence analysis: a new price high with a lower TSI high shows momentum fading.
- It works on any symbol and timeframe, with H1 to D1 giving the cleanest swings.
Settings
| Input | Default | What it changes |
|---|---|---|
| First (long) smoothing length | 25 | Main smoothing; longer is slower and steadier |
| Second (short) smoothing length | 13 | Final smoothing; shorter reacts faster |
| Signal line EMA length | 7 | Speed of the signal line and of crosses |
| Overbought / oversold level | 25 | Position of the reference levels and the zone filter |
| Only mark crosses beyond the level | false | Fewer, more selective arrows when on |
| Pop-up alert / Push notification | false / false | One alert per closed bar on a new cross |
Limitations
- Double smoothing reduces noise but adds lag; turns in TSI come after turns in price.
- Signal-line crosses are frequent in sideways markets.
- The ±25 levels are a convention, and suitable levels differ by instrument and timeframe.
- The EMAs are seeded at the start of the chart history, so the first bars are less accurate.
- The live bar's values change with each tick; arrows and alerts are confirmed on the close. Trading involves substantial risk of loss.