Price Rate of Change (ROC) Indicator

The Price Rate of Change (ROC) indicator is a momentum oscillator that measures the percentage change between the current price and the price a defined number of periods ago. A positive ROC means price is higher than it was n periods back. A negative ROC means it is lower. The further from zero in either direction, the stronger the momentum. Traders use ROC to identify overbought and oversold conditions, spot divergences between price and momentum, and confirm trend strength.

Think of ROC like a car's acceleration gauge: it does not show how fast you are going, it shows whether you are speeding up or slowing down.

The ROC Formula

The calculation is straightforward: subtract the closing price n periods ago from today's closing price, divide by the closing price n periods ago, then multiply by 100 to express the result as a percentage. A 12-period ROC on a daily chart compares today's price to the price 12 trading days ago.

The choice of n determines the indicator's sensitivity. Short periods like 5 or 10 make ROC highly sensitive and prone to noise. Longer periods like 20 or 25 smooth the signal and better capture meaningful trend momentum.

How Traders Read the ROC

ROC oscillates above and below a zero line, and that centerline is the key reference point for all interpretations.

• ROC crossing above zero: Price has risen versus n periods ago. Often read as a bullish signal, particularly when the crossing follows a prolonged negative period.
• ROC crossing below zero: Price has fallen versus n periods ago. Often read as a bearish signal in a declining trend.
• Extremely high ROC readings: Signal that price may have moved too far, too fast, and is overbought relative to recent history. A pullback or consolidation becomes likely.
• Extremely low ROC readings: Signal oversold conditions where selling momentum has become extreme and a bounce may be due.

Divergence Signals Are the Strongest ROC Application

The most reliable ROC signals come from divergences between price and momentum. A bullish divergence occurs when price makes a new low but ROC makes a higher low, indicating that sellers are losing strength even as price continues falling. A bearish divergence occurs when price makes a new high but ROC makes a lower high, signaling weakening buying pressure behind what appears to be a continuing uptrend.

Divergences do not give precise entry points. They warn that the trend may be running out of energy. You still need confirmation from a price signal, such as a break of support or resistance, before acting.

ROC vs. MACD

Sources

• https://school.stockcharts.com/doku.php?id=technical_indicators:rate_of_change_roc_and_momentum
• https://www.cboe.com/education/