Mass Index — what it is and how to use it in trading
Definition
The Mass Index is a volatility indicator measuring how much the range (high-low) of individual candles is expanding and contracting, regardless of the direction price is moving.
How it works in the builder
The mass_index operand takes window_fast/window_slow parameters (default 9 and 25). By the classic formula, a strong but short-lived "bulge" above the 27 level followed by a drop is read as a sign of a reversal, without indicating its direction.
What it looks like on the chart
Drawn as a separate panel as a mostly flat line with an occasional sharp spike and a dashed level at 27 — the spike itself is visually obvious against a calm stretch of the line.
Typical use
Typical condition: mass_index(9, 25) crossed_below 27 after the line has been above that level — the classic "reversal bulge". The direction of the reversal still needs to be confirmed with a separate trend or price condition.
Common pitfalls
Mass Index only signals the likelihood of a range reversal, but says nothing about its direction — it is used as a volatility filter combined with a directional indicator, not as a standalone signal.
This block is available in the strategy builder
137 no-code blocks — build an entry condition with this term and test it on history
Historical results do not guarantee future ones. The service is an informational and analytical tool, not an individual investment recommendation; trades are not executed.