What Is MACD? Moving Average Convergence Divergence Explained

The MACD line is the 12-period EMA minus the 26-period EMA. The signal line is a 9-period EMA of the MACD line. The histogram is the difference between the two.

When the MACD line is above zero, the fast average is above the slow one and the trend is up on that timeframe. When it crosses above the signal line, short-term momentum has turned up relative to its own recent average.

The classic signal is a crossover: MACD crossing above the signal line is read as bullish, below as bearish. In a ranging market this produces a stream of losing signals, because the averages whip back and forth around each other.

The zero-line cross is slower and generally more meaningful — it marks the point where the fast and slow averages actually change order, which usually corresponds to a genuine shift in trend rather than a pause.

As with RSI, divergence is where MACD earns its place. A new price high accompanied by a lower MACD high means the second leg was driven by less momentum than the first.

The histogram often shows this earliest. Shrinking bars while price continues in the same direction means the move is decelerating — useful for trailing a stop or taking partial profit long before any crossover appears.

MACD is built from moving averages, so it inherits their weakness: it is bad in ranges and late at turns. In a sideways market it will generate crossover after crossover, each one a small loss.

The usual fix is a regime filter. Only act on MACD signals when a separate measure says the market is trending — ADX above a threshold, price holding one side of a higher-timeframe moving average, or simply a visibly higher-high/higher-low structure.