The exponential moving average (EMA) differs from a simple moving average (SMA) in two primary ways: more weight is given to the most recent data and the EMA reacts faster to recent price changes than the SMA.
The EMA is very popular in forex trading, so much that it is often the basis of a trading strategy. A common forex trading strategy that uses EMAs relies on selecting a shorter-term EMA and a longer-term EMA and then trade based on the position of the short-term EMA in relation to the long-term EMA. A trader enters buy orders when the short-term EMA crosses above the long-term EMA or enters sell orders when the short-term EMA crosses below the long-term EMA.
For example, a trader might use crossovers of the 50 EMA by the 10 or 20 EMA as trading signals. Another strategy that forex traders use involves observing a single EMA in relation to price to guide their trading decisions. As long as the price remains above the chosen EMA level, the trader remains on the buy side; if the price falls below the level of the selected EMA, the trader is a seller unless price crosses to the upside of the EMA.
The most commonly used EMAs by forex traders are the 5, 10, 12, 20, 26, 50, 100, and 200. Traders operating off of shorter timeframe charts, such as the five- or 15-minute charts, are more likely to use shorter-term EMAs, such as the 5 and 10. Traders looking at higher timeframes also tend to look at higher EMAs, such as the 20 and 50. The 50, 100 and 200 EMAs are considered especially significant for longer-term trend trading.