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Good Trading Guide

MACD Explained: Moving Average Convergence Divergence

Module 6B: Indicators · Lesson 3 of 10 · Back to course

MACD (usually said “mac-dee”) looks complicated: two lines, a histogram and a zero line. In fact it’s built entirely from moving averages, which you’ve already met. Once you see that, it becomes one of the easier indicators to read – and easier to see its limits.

What it is

MACD stands for Moving Average Convergence Divergence. It was developed by Gerald Appel in the late 1970s. It sits in a panel under the chart and has three parts:

  • The MACD line: the gap between a faster and a slower moving average of price.
  • The signal line: a moving average of the MACD line itself.
  • The histogram: bars showing the gap between the MACD line and the signal line.

The standard settings are 12, 26 and 9. MACD is usually grouped with trend indicators, but because it measures how fast the two averages are pulling apart, it also carries momentum information.

How it’s calculated (in plain English)

  1. Work out a 12-period exponential moving average (EMA) of closing prices. An EMA is an average that gives more weight to recent candles.
  2. Work out a 26-period EMA of closing prices.
  3. MACD line = 12 EMA − 26 EMA. When the faster average is above the slower one, the MACD line is above zero; when it’s below, the line is below zero.
  4. Signal line = 9-period EMA of the MACD line. It’s a smoothed, slower version of the MACD line.
  5. Histogram = MACD line − signal line. Bars above zero mean the MACD line is above its signal line; bars below zero mean it’s beneath.

“Convergence” means the two averages are getting closer together (momentum slowing). “Divergence” here just means they’re moving apart (momentum building). That’s a different use of the word from the price-vs-indicator divergence in Lesson 6B.9.

How traders use it

1. Zero line as a trend filter. MACD above zero means the 12 EMA is above the 26 EMA – a short-term upward bias. Below zero means the opposite. Some traders only consider buys when MACD is above zero. It’s very similar to the logic of the Moving Average Crossover Strategy, because a MACD zero-line cross is a 12/26 EMA crossover.

2. Signal-line crosses. The MACD line crossing above its signal line is often read as momentum turning up; crossing below as momentum turning down. These crosses happen often, and in sideways markets many of them reverse quickly. They’re a weak stand-alone trigger.

3. The histogram as a momentum gauge. Shrinking histogram bars mean the MACD line and signal line are converging – momentum is slowing, even if price is still rising. That’s information, not a signal to reverse.

4. Divergence. Price making a higher high while MACD makes a lower high is a sign momentum is fading. See Lesson 6B.9.

Common mistakes

  • Trading every signal-line cross. In ranges, MACD crosses back and forth and produces a string of small losses (plus spread on every trade).
  • Forgetting MACD lags twice. It’s built from moving averages, and the signal line is an average of an average. Crosses usually arrive well after the turn in price.
  • Comparing MACD values across markets. MACD is measured in price units – pips on GBP/USD, points on the FTSE 100 – so a reading of “20” means very different things on different instruments, and even on the same instrument at different price levels.
  • Using MACD alongside a 12/26 moving average crossover and calling it confirmation. It’s the same calculation.
  • Tweaking 12/26/9 until past crosses look perfect. That’s curve-fitting.

Example (illustrative numbers)

All figures are made up for teaching purposes. They aren’t real prices or a trade idea.

On a 4-hour GBP/USD chart:

  • 12-period EMA = 1.2710
  • 26-period EMA = 1.2690
  • MACD line = 1.2710 − 1.2690 = 0.0020 (20 pips)
  • Signal line (9-period EMA of MACD) = 0.0015 (15 pips)
  • Histogram = 0.0020 − 0.0015 = +0.0005 (5 pips)

Reading it: the faster average is above the slower one (upward bias), and the MACD line is above its signal line (momentum still rising). Now suppose over the next three candles price edges higher but the histogram shrinks from +5 to +3 to +1 pip. Momentum is slowing. A trader’s plan might say “don’t open new buys when the histogram is shrinking” or “tighten nothing; follow the original stop”. What it shouldn’t say is “price must reverse now”.

The prop firm angle

Challenge rules punish strings of losses. MACD signal-line crosses in choppy, sideways markets are a classic source of exactly that. If MACD is part of your plan:

  • Prefer using it as a filter (zero line) over a trigger (signal-line crosses).
  • Combine it with a way of identifying ranges – for example, standing aside when price is stuck between clear levels.
  • Count how many crosses a given week produced on your demo and how many reversed within a few candles. That gives you a realistic idea of how often you’d be trading, and paying the spread.

Key takeaways

  • MACD line = 12 EMA − 26 EMA; signal line = 9 EMA of the MACD line; histogram = the gap between them.
  • Above zero: short-term average above the longer one. Below zero: the opposite.
  • Signal-line crosses are frequent and lag; in sideways markets many reverse quickly.
  • MACD is measured in price units, so values aren’t comparable between markets.

Quick quiz

  1. What are the three parts of MACD? (MACD line, signal line, histogram.)
  2. If the 12 EMA is 8,150 and the 26 EMA is 8,170 on the FTSE 100, what is the MACD line? (−20 points.)
  3. What does a shrinking histogram tell you? (The MACD and signal lines are converging – momentum is slowing.)
  4. Why does a MACD zero-line cross add little to a 12/26 EMA crossover? (It’s the same event – MACD crosses zero exactly when the 12 EMA crosses the 26 EMA.)
  5. In what kind of market do signal-line crosses tend to give most false signals? (Sideways/ranging markets.)

Key terms

MACD · Exponential moving average (EMA) · Signal line · Histogram · Crossover · Momentum · Also see Trading jargon in plain English.

Try this

On a demo chart, add MACD(12, 26, 9) to a 1-hour chart of the DAX or FTSE 100. Over one week, mark every signal-line cross. For each, note whether price moved at least 20 points in the direction of the cross before moving 20 points against it. Then mark which crosses happened while price was in a range. The point isn’t to find a rule – it’s to see how many crosses a lagging indicator produces.

FAQ

Is MACD a trend or momentum indicator? Both. It’s built from moving averages (trend), but the histogram and convergence/divergence show changing momentum.

What does MACD crossing zero mean? That the 12-period EMA has crossed the 26-period EMA.

What are the best MACD settings? 12, 26, 9 is the standard. Changing them to fit past charts is curve-fitting.

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6B.4 Bollinger Bands →

Disclaimer: This page is general education, not financial or investment advice or a personal recommendation, and it doesn’t take your circumstances into account. Examples are hypothetical, for illustration only, and not an invitation to buy or sell. Learning a strategy doesn’t guarantee profits. Past performance is not a reliable guide to future results. Futures, spread bets and CFDs are complex and carry a high risk of losing money quickly because of leverage, and most retail traders lose money. With a real futures account, losses can exceed your deposit. Only trade with money you can afford to lose, and speak to an independent FCA-authorised adviser if you’re unsure. Read our full risk warning.