A moving average is the simplest trend tool on any chart. By averaging recent closes, it filters out the bar-to-bar noise and shows whether price is generally rising, falling or flat. Unless stated otherwise, “moving average” usually means the simple moving average (SMA); the faster-reacting variant is the EMA.
How it’s calculated
SMA = (sum of the last N closes) ÷ N
Each new period, the oldest close drops out and the newest is added, so the line “moves”.
Widely used settings:
- 20-period: short-term trend; also the middle line of Bollinger Bands.
- 50-period: medium-term trend.
- 200-period: long-term trend, closely watched on daily charts.
Typical uses: the slope shows the trend direction, price above or below the average shows bias, and rising averages often act as dynamic support (falling ones as resistance). Crossovers of a fast and a slow average are a basic trend-following signal.
Example
A 5-period SMA on closes of 10, 11, 12, 13 and 14:
- SMA = (10 + 11 + 12 + 13 + 14) ÷ 5 = 12
The next close is 15. The 10 drops out:
- SMA = (11 + 12 + 13 + 14 + 15) ÷ 5 = 13
Notice that price is at 15 while the average is at 13: the SMA trails price by design. On a longer setting such as 200 periods, that lag is much larger.
Common mistakes
- Expecting averages to predict. They describe what has already happened. Crossovers usually arrive after a good part of the move.
- Using them in ranges. In sideways markets, price crosses a flat average constantly, producing false signals.
- Treating the line as an exact level. Price often overshoots a moving average before reacting; think of it as a zone.
- Optimising the period endlessly. Fitting the “perfect” length to past data rarely holds up; standard settings are easier to compare.
The MACD is built from two EMAs and turns their gap into a momentum reading. For how averages combine with other indicators, see RSI, MACD, ATR and EMA explained.
Educational content — not financial advice.
Updated