MACD, developed by Gerald Appel in the late 1970s, turns two exponential moving averages into a momentum gauge. When the shorter average pulls away from the longer one, momentum is building; when they converge, it is fading. Because it is built from averages, MACD confirms trends rather than predicting them.
How it’s calculated
- MACD line = 12-period EMA − 26-period EMA
- Signal line = 9-period EMA of the MACD line
- Histogram = MACD line − signal line
Common readings:
- Zero-line cross: MACD above zero means the 12 EMA is above the 26 EMA (bullish bias); below zero, the opposite.
- Signal-line cross: MACD crossing above or below its signal line.
- Divergence: price makes a new high or low that MACD does not confirm.
MACD has no fixed upper or lower bound, so its values are not comparable across instruments with different prices.
Example
On a daily chart, the 12-period EMA is 105.40 and the 26-period EMA is 103.90.
- MACD = 105.40 − 103.90 = 1.50
- The signal line (9-period EMA of MACD) is at 1.20
- Histogram = 1.50 − 1.20 = +0.30
MACD is positive and above its signal line: the bullish bias is intact. Over the next days, if the histogram shrinks from +0.30 to +0.10 while price makes a marginal new high, momentum is slowing. That is a warning, not a sell signal; a confirming price event, such as a break below support, would carry more weight.
Common mistakes
- Trading every crossover. In sideways markets, MACD crosses back and forth and produces repeated losses.
- Forgetting the lag. Built from 12-, 26- and 9-period averages, MACD reacts after the move has started. A breakout from a symmetrical triangle often happens before MACD turns.
- Comparing raw values across assets. A MACD of 1.5 on a $100 stock and on a $20 stock mean very different things.
- Using it as a timing tool alone. Pair it with price structure and an oscillator like RSI.
See RSI, MACD, ATR and EMA explained for how the four work together.
In SnapPulse
SnapPulse reads MACD on your scanned chart and explains it in plain language next to RSI, ATR and EMA. Download SnapPulse.
Educational content — not financial advice.
Updated