MACD condenses two moving averages into a single trend-and-momentum signal — its standard settings aren't arbitrary, they're the decades-old default nearly every charting platform still ships with.
The Formula and Components
MACD line = 12-period EMA − 26-period EMA. The signal line is a 9-period EMA of the MACD line itself. The histogram plots the gap between the two, visually showing convergence or divergence. A standard signal: MACD crossing above the signal line suggests strengthening upward momentum; crossing below suggests the reverse — though like any single indicator, it's most reliable combined with price action and volume confirmation, not used alone.
Worth knowing: The MACD histogram's shrinking size — even while price is still moving in the same direction — often precedes a signal-line crossover, giving a earlier heads-up on weakening momentum than waiting for the crossover itself.
Someone New to Technical Indicators: MACD's 12/26/9 default settings are a reasonable, well-tested starting point before experimenting with custom periods.
Someone Trading Short-Term Swings: Watch the histogram's shape, not just crossovers, for an earlier momentum read.
Use MACD the Way
- Start with the standard 12/26/9 settings.
- Watch histogram shape for early momentum shifts, not just crossovers.
- Confirm signals with price action and volume before acting.
See RSI explained and moving averages explained for the building blocks MACD is derived from.
