What is the Simple Moving Average (SMA) Indicator?
The Simple Moving Average (SMA) is a trend-following indicator that plots the average price over a fixed lookback period as a single line on the price chart. Traders use it to smooth short-term volatility, judge trend direction from the line’s slope, and track dynamic support and resistance as price interacts with the average. Common defaults are the 20-period, 50-period, and 200-period SMA, and the indicator has no fixed range because it stays in price units.
How is the Simple Moving Average (SMA) Indicator Calculated?
The SMA is calculated by summing the last N prices (most platforms use the close) and dividing by N: SMA = (P1 + P2 + ... + PN) / N, where N is the lookback period. With each new candle, the calculation rolls forward by adding the newest price and removing the oldest price from the window, which is why the line “moves.” The default input is typically Close and a user-selected period such as 20, 50, or 200.
How to Use the Simple Moving Average (SMA) Indicator in Trading?
To use an SMA in trading, treat it as a trend filter and a moving reference level, then take signals only when price action confirms the direction the average implies.
- Trend direction filter: trade long when price holds above a rising SMA; trade short when price holds below a falling SMA.
- Dynamic support/resistance: in an uptrend, buy pullbacks that tag the SMA and reject (e.g., wick into the line, close back above); in a downtrend, sell rallies that fail at the SMA and close back below.
- SMA crossovers: a faster SMA crossing above a slower SMA signals strengthening upside momentum; crossing below signals strengthening downside momentum (commonly 50/200 for “golden cross” and “death cross”).
- Stops and invalidation: place the stop beyond the SMA and the most recent swing (e.g., below the swing low plus the SMA for longs) so a clean break invalidates the setup.