Rate of Change (ROC)
Percent change between the current close and the close n periods ago; positive values confirm upward momentum, negative values confirm selling pressure.
ROC = ((Close − Close_n) / Close_n) × 100
Rate of Change simply computes how much price has moved, expressed as a percentage, relative to a fixed lookback (default 9–14 periods). It is an unbounded momentum oscillator — no overbought/oversold thresholds exist by default.
Traders use the zero line as a trend filter: positive ROC = bullish momentum, negative ROC = bearish. A declining ROC peak-to-peak while price makes new highs is a classic momentum divergence warning. It is the simplest form of momentum indicator, and forms the mathematical core of the Coppock Curve.