The MACD (Moving Average Convergence Divergence) measures the relationship between two moving averages. The MACD line is the 12-period EMA minus the 26-period EMA. The signal line is a 9-period EMA of that, and the histogram is the gap between them. Crossovers hint at momentum shifts, and divergence warns a trend is weakening. Like all averages, it lags.
What the MACD is
The MACD is a momentum-and-trend indicator built from moving averages. At its core it measures how far a fast average has pulled away from a slow one. When they spread apart, momentum is strong. When they converge, it is fading. The standard settings are 12, 26 and 9.
Because it is derived from EMAs, the MACD inherits their strengths and weaknesses. It describes trend momentum well, but it is always a step behind live price.
The three components
Confusion usually comes from not separating the three parts.
- MACD line. The 12-EMA minus the 26-EMA. Above zero means the faster average is higher, which is bullish momentum.
- Signal line. A 9-EMA of the MACD line. It is a smoothed version used to spot turns.
- Histogram. The MACD line minus the signal line, drawn as bars.
Crossovers
The classic signal is the MACD line crossing the signal line. Up through it is a bullish cue and down through it is bearish. The zero-line cross is separate and slower. MACD crossing above zero means the fast EMA has overtaken the slow one, confirming a trend shift.
As with moving-average crossovers, these are late and whipsaw in ranges. They confirm momentum rather than pinpoint entries. They work far better in the direction of the higher-timeframe trend.
The histogram and momentum
The histogram is often the most useful part. When the bars are growing, the lines are separating and momentum is accelerating. When they are shrinking, momentum is fading even if price is still edging higher.
A histogram that peaks and starts contracting is an early hint that a move is losing steam, earlier than the crossover it eventually produces. It is a momentum gauge, not a trade trigger on its own.
MACD divergence
Like the RSI, the MACD can diverge from price. A higher high in price with a lower high in the MACD warns that the advance is running on weaker momentum. Bullish divergence is the mirror image at lows.
Divergence is a heads-up. It is not a signal to fade the trend immediately. Combine it with a level and a price trigger, and treat it as a reason to tighten risk, not to reverse on the spot.
Limitations
The MACD is a lagging, average-based tool. It is late at turns and noisy in sideways markets, where you will see crossover after crossover, most of them worthless. It also has no fixed scale, so high and low readings are relative to the instrument, unlike the RSI's 0–100.
Used well, MACD confirms trend and flags fading momentum. Used badly, it becomes a crossover-chasing machine. Pair it with structure, respect the trend, and size every trade from the stop.
Questions
What does the MACD histogram show?
The gap between the MACD and signal lines. Growing bars mean momentum is accelerating. Shrinking bars mean it is fading, which can hint at a slowing move before a crossover.
What is the main limitation of the MACD?
It lags, so it is late at turns and gives many false crossovers in sideways markets. It also has no fixed scale.
70–80% of retail investor accounts lose money trading CFDs. This page is education, not advice. All trade examples are constructed composites.
