A moving average smooths price into a single line so you can see the trend without the noise. It is the foundation of many other indicators, including MACD and Bollinger Bands.
SMA vs EMA
- Simple moving average (SMA): the average closing price of the last n periods.
- Exponential moving average (EMA): a weighted average that emphasizes recent prices, so it turns sooner.
Short-term traders tend to prefer EMAs for responsiveness; long-term investors often use SMAs.
The periods that matter
| Period | Typical use |
|---|---|
| 9 / 10 EMA | Short-term momentum, intraday trends |
| 20 EMA | Swing trading pullbacks |
| 50 SMA | Intermediate trend |
| 200 SMA | Long-term trend filter |
Because so many traders watch the same averages, they can become self-fulfilling reference points.
Three moving average strategies
1. The trend filter
Only take long trades when price is above the 200-period average and shorts when below. This single rule removes many low-probability counter-trend trades.
2. Pullback to the 20 EMA
In a strong trend, price often pulls back to the 20 EMA before continuing. Enter when a bullish candle forms at the average, with a stop below the pullback low.
3. Crossovers
A short average crossing above a long one (such as the 50 above the 200, the “golden cross”) signals a possible trend change. Crossovers lag, so they suit position trading better than short-term timing.
How the averages are calculated
SMA. The 5-period SMA of closes 10, 11, 12, 11 and 13 is (10 + 11 + 12 + 11 + 13) ÷ 5 = 11.4.
EMA. Each new value moves part of the way toward the latest close:
EMA = previous EMA + k × (close − previous EMA), where k = 2 ÷ (n + 1)
For a 10-period EMA, k = 2 ÷ 11 ≈ 0.182. If the previous EMA is 100 and the new close is 104, the EMA becomes 100 + 0.182 × 4 ≈ 100.73. A 10-period SMA would instead change by (new close − the close dropped from the window) ÷ 10, treating old and new prices equally.
Example: a 20 EMA pullback on EUR/USD
On the 4-hour chart EUR/USD is above a rising 50 SMA. Price pulls back to the 20 EMA and prints a bullish engulfing candle that closes at 1.0925.
- Entry: 1.0925 on the close
- Stop: below the pullback low at 1.0898 — 27 pips
- Target: 2R, 1.0925 + 0.0054 = 1.0979
- Size: risking $100, $100 ÷ (27 × $10) ≈ 0.37 lots
Run your own numbers with the position size calculator.
Common mistakes
- Trading crossovers in a range. Flat averages cross back and forth and produce a string of small losses.
- Treating the average as an exact line. Price often overshoots it; use the candle’s close and structure, not a touch.
- Stacking too many averages. Five lines on one chart rarely add information.
- Changing periods to fit recent data. Pick standard periods and test them over a large sample.
Limitations
Moving averages lag by design and generate whipsaws in sideways markets. Use them to define direction, and use price structure to time entries.
Frequently asked questions
What is the difference between an SMA and an EMA?
A simple moving average weights every period equally. An exponential moving average gives more weight to recent prices, so it reacts faster to new moves.
Which moving averages do professional traders watch?
The 20, 50 and 200-period moving averages are the most widely followed, with the 200-day average often used as the dividing line between long-term uptrends and downtrends.
What is the best moving average for day trading?
Many day traders use the 9 or 20 EMA on 5-minute charts for short-term direction and VWAP as the main intraday reference. There is no single best average; consistency matters more than the exact period.
Is the golden cross a buy signal?
A golden cross (the 50-day crossing above the 200-day) signals that the long-term trend may be turning up, but it lags price significantly. Many traders use it as a background filter rather than an entry trigger.
How many moving averages should I use?
Two or three is plenty — for example a short average for pullbacks, a medium one for the trend and the 200-period as a long-term filter. More averages add clutter without adding information.