Exponential Moving Average (EMA)

The exponential moving average (EMA) is a moving average that gives more weight to recent prices and less to older ones, with the weight fading exponentially the further back you go. Because recent prices matter most, the EMA reacts faster to new moves than a simple moving average of the same length. It is the foundation of the MACD indicator and a favourite of short term traders.

The formula#

EMA today = (Price today × k) + (EMA yesterday × (1 − k))
k = 2 ÷ (n + 1)

Here n is the EMA period and k is the smoothing factor. For a 20 period EMA, k = 2 ÷ 21 ≈ 0.095, so today's price gets about 9.5% of the weight, and the previous EMA carries the rest. The first EMA value is usually seeded with a simple moving average.

Why traders like the EMA#

• Faster reaction: turns sooner when trends change.
• No drop off effect: old prices fade gradually instead of falling out of the window abruptly.
• Smooth enough for trend: still filters noise compared with raw price.

The trade off is more false signals in choppy markets, because the EMA responds to every move.

Popular EMA settings#

Trading with the EMA#

Pullbacks to a rising EMA#

In strong uptrends, price often pulls back to the 20 or 21 period EMA and bounces. Traders wait for a reaction, such as a bullish candle closing back above the EMA, then enter with a stop below the pullback low.

EMA ribbons and stacks#

Some traders plot several EMAs, such as 8, 21 and 55. When they are stacked in order (shortest on top in an uptrend) and fanning apart, the trend is strong. When they twist together, the market is ranging.

Crossovers#

A fast EMA crossing a slow EMA signals momentum shifts. The difference between the 12 and 26 period EMAs is exactly what MACD measures. See MACD.

EMA vs SMA vs WMA#

See Simple Moving Average (SMA) and Weighted Moving Average (WMA).

Practising with EMAs#

A good exercise is to add a 20 period EMA to a daily chart of a trending market and mark every pullback that touched it. Note how many held, how far price overshot before turning, and what the candles looked like when the EMA failed. Any charting platform with moving averages will do. The goal is not to find a magic setting, but to learn how the EMA behaves in trends and ranges so you can tell when it is likely to help.

Common mistakes#

• Using short EMAs in sideways markets, generating constant crossovers.
• Assuming the EMA is always better because it is faster; speed adds noise.
• Comparing EMA levels across platforms that seed the calculation differently, causing small differences.

Frequently asked questions#

Why is the EMA faster than the SMA?#

Because it gives more weight to recent prices, so new moves affect it immediately and strongly.

What is the best EMA for day trading?#

Many day traders use the 9 and 20 period EMAs on intraday charts, but the right choice depends on your strategy and timeframe.

How is the EMA smoothing factor calculated?#

It is 2 divided by the period plus 1. For a 20 period EMA, that is about 0.095.

Next, learn the linear weighted alternative: the Weighted Moving Average (WMA).