How it works
TRIX takes an exponential moving average of price, then an exponential average of that, then an exponential average of that. The triple smoothing removes essentially all short-term noise — cycles shorter than the chosen length are filtered out almost entirely — and what remains is a very clean curve describing the underlying drift. TRIX then plots the percentage change of that curve from one bar to the next.
The result is a momentum oscillator built out of a trend tool. Zero has a precise meaning: the triple-smoothed line is flat, so the underlying drift has stalled. Above zero the smoothed trend is rising, below zero it is falling, and the distance from zero measures how fast. Because the input has been smoothed three times, the oscillator is slow, but it is also remarkably free of the false crossings that plague single-smoothed momentum measures.
Traders use it in three ways. The zero-line cross is the primary trend signal and is deliberately infrequent. A signal line, usually a short exponential average of TRIX itself, provides earlier crossovers for those who want them. And divergence against price is comparatively meaningful here, because the triple smoothing means a lower TRIX peak reflects a genuine loss of underlying drift rather than a couple of soft bars.
Note a scaling detail that confuses people comparing platforms: the classic definition is the percentage change of the triple EMA, but many implementations, including several charting packages, apply the smoothing to the natural logarithm of price and multiply the result by 10,000 to express it in basis points. The two agree closely for ordinary bar-to-bar changes; only the axis labels differ.
Against MACD, its closest relative, TRIX is slower and cleaner. MACD measures the spread between two averages and reacts to changes in that spread; TRIX measures the slope of one heavily filtered average. That makes MACD better for catching a turn early and TRIX better for staying in a trend without being shaken out by noise. Know Sure Thing and the Coppock Curve occupy the same slow-momentum territory from a rate-of-change starting point.
Calculation
The arithmetic in words, in the order it happens.
Compute an exponential moving average of the source over N periods. Take an exponential moving average of that result over the same N, and then a third over the same N again. TRIX is the percentage change of the final series from the previous bar to the current one: the difference divided by the previous value, multiplied by 100. Implementations that smooth the natural logarithm of price instead publish the same quantity scaled by 10,000, in basis points. An optional signal line is a short exponential average, conventionally 9 periods, of TRIX itself.
Source
An AlgoBeamScript implementation of the formula above, written by us from the arithmetic so the code and the calculation agree line for line.
Runs unchanged on the platform and in the AlgoBeamTS runtime. The language reference is in the documentation.
Inputs
Defaults are the values most charting packages ship with. They are conventions, not optimal settings — the right length depends on your instrument and your holding period.
| Input | Default | What it changes |
|---|---|---|
| Length | 18 | The period used for all three smoothings, so its effect compounds. Shorter values such as 9 give a livelier oscillator with more zero crossings; 18 and above filter out virtually everything except the primary trend. |
| Signal length | 9 | Smoothing for the optional trigger line. Shorter values produce earlier crossovers and more of them; without a signal line the zero cross is the only mechanical signal, which is very late but very clean. |
| Source | Close | The price series entering the first average. Because of the triple smoothing the choice of source barely affects the output — one of the few indicators where it genuinely does not matter much. |
How to read it
What practitioners take from the plot. Read these as descriptions of market state, not as entry signals.
- TRIX crossing above zero
- The triple-smoothed trend has turned upward. Slow and infrequent, which is the point: it filters out the moves that were never trends.
- TRIX rising and above zero
- The underlying drift is upward and accelerating. The healthiest state for a trend-following position and the environment in which pullbacks tend to be shallow.
- TRIX above zero but falling
- The trend is still up but decelerating. A warning about pace, not direction; trends can decelerate for a long time without reversing.
- Price at a new high, TRIX peaking lower
- The new extreme was achieved on less underlying drift. More trustworthy than divergence on a fast oscillator, because triple smoothing rules out noise as the cause.
- TRIX oscillating tightly around zero
- No underlying trend at any timescale the filter can see. Zero crossings here are meaningless and should be ignored.
Limitations
Where this indicator misleads. None of these are fixed by a better parameter.
- Triple smoothing means substantial lag. Zero-line crossings arrive well after a trend has begun and well after it has ended, so a large part of every move is given up at both ends.
- On short lookbacks it can still whipsaw around zero in a range, and because each crossing looks authoritative after all that smoothing, those false signals are unusually convincing.
- It is a pure trend-slope measure with no volatility or volume input, so it cannot distinguish a slow grind higher on no participation from a strong, broad advance.
- Scaling differs between platforms — percentage change versus basis points on log price — so absolute thresholds copied from one chart to another will be wrong by orders of magnitude.
Educational reference. This page explains how an indicator is built and how it is commonly read. It is not investment advice, not a recommendation and not a signal service. No indicator is profitable on its own — each is a way of describing a market, and any rule built on one has to be tested with realistic costs before it is traded.