MACD
A momentum indicator built from the difference between two exponential moving averages.
Also called: moving average convergence divergence
Written by Javier Sánchez Ros
In plain language
MACD subtracts a longer EMA from a shorter one — classically 26 and 12 periods. A signal line, usually a 9-period EMA of that result, is plotted on top.
The histogram shows the gap between the MACD line and its signal line. It expands when momentum is accelerating and contracts when the move is tiring.
Because it is built entirely from moving averages, MACD inherits their lag. It confirms moves rather than anticipating them.
The formula
MACD Line
12-period EMA − 26-period EMA
- Signal line
- 9-period EMA of the MACD line
- Histogram
- MACD line − Signal line
Worked through
A histogram shrinking while price still rises
- Price
- making new highs
- Histogram bar 1
- 0.42
- Histogram bar 2
- 0.31
- Histogram bar 3
- 0.19
Price is still going up and the rate at which it is going up is falling. The histogram measures the gap between the MACD line and its signal line, so a shrinking sequence says the move is decelerating while still moving.
That is a genuinely useful thing to know, and it is not a sell signal. Trends decelerate and re-accelerate constantly. What it is, for a trader already long, is a reason to tighten a trailing stop rather than to add — a change in how the position is managed, not a reversal of the view.
Used as an entry trigger the tool is much weaker. MACD is built from two moving averages, so it inherits their lag twice over, and a crossover signal in a choppy market arrives after the move it is describing has mostly happened.
Its honest description is a momentum gauge with a delay. Read the histogram’s direction rather than its crossings, treat it as commentary on a position you already have, and it does real work; treat it as a signal generator and it mostly generates late ones.
Why it matters
MACD offers a structured read on whether momentum is building or fading, which is useful for deciding whether to hold a trend trade or tighten the trail.
Common mistakes
- Trading every crossover regardless of trend context.
- Using MACD in a sideways market, where it produces near-continuous false signals.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
A moving average that weights recent prices more heavily than older ones.
When price makes a new extreme but the indicator does not, suggesting momentum is fading.
A momentum oscillator from 0 to 100 that compares the size of recent gains to recent losses.
A sustained directional bias in price, built from a repeating pattern of highs and lows.
The average price over a set number of periods, recalculated as each new period closes.