Rate of Change

Rate of Change measures the percentage change between the current price and the price a fixed number of bars ago, plotting the result as an oscillator around a zero line so traders can read momentum in comparable percent terms. With the default length of 9, each reading answers one question: how far, in percent, has price traveled over the last nine bars? A mode input switches from ROC % (the default) to Momentum, which plots the raw price difference instead of the percentage. This is the standard raw implementation of the indicator.

How to Trade the Rate of Change?

• ROC above zero: price is above where it stood a lookback ago — momentum is positive.
• ROC below zero: price has lost ground over the window.
• Zero cross up: the lookback comparison turns positive — a regime shift covered by an included alert.
• Zero cross down: the opposite shift, likewise covered by an alert.
• Extremes: the scale has no fixed bounds, so what counts as stretched comes from the instrument's typical range.
• Divergence: a new price extreme on a smaller ROC swing shows the rate of advance decaying.

A reading of 5 means five percent on any symbol at any price — portability no raw point difference offers.

Rate of Change Settings

• Length (default 9): the lookback period; the source is compared with its value this many bars ago. Shorter lengths make a twitchy line that catches bursts, while longer lengths describe broader momentum and cross zero less often.
• Source (default close): the series used as input for the calculation.
• Mode (default ROC %): ROC % plots the change as a percentage of the source value from the lookback; Momentum plots the raw difference in price units.

Frequently Asked Questions

When should I use Momentum mode instead of ROC %?

Momentum shows the move in actual price units, useful when thinking in points or dollars on a single instrument. ROC % is the better default everywhere else — for screening, comparing symbols, and judging today's reading against older history.

What is the best length for Rate of Change?

The default 9 is a general-purpose window that works on any timeframe. Shorter settings suit burst-detection styles that want every acceleration flagged; longer ones suit trend confirmation where only sustained moves should register. Match the length to how long the moves you trade actually last.

Why can the line move sharply while price barely changes?

The reading compares just two prices, so it shifts whenever either end moves — and the old end changes every bar as the lookback rolls forward. A large bar aging out of the window can swing the line on a quiet session, so glance at what just left the comparison before acting on a sudden change.