An exponential moving average, or EMA, is a moving average that gives newer price observations more weight than older ones. It is commonly plotted on a price chart to help describe trend direction and changes in momentum.
Updating the average
Each update combines the current input price with the previous EMA. With a smoothing weight of 20%, a previous EMA of $100 and a new closing price of $110 produce a new EMA of $102: 20% of $110 plus 80% of $100.
The selected length influences the usual smoothing weight. Shorter settings generally react faster, while longer settings smooth more. Unlike a simple moving average’s fixed window, an EMA carries older information forward through its previous value, with diminishing influence.
Reading it consistently
An EMA’s value depends on the price source, timeframe, settings and starting calculation. Comparing charts therefore requires consistent inputs. A value based on an unfinished candle can change before that candle closes.
Traders may examine slope or crossovers, but quicker reaction does not remove lag or false signals. Repeated crossings in a sideways market can produce costly trades without establishing a lasting trend.