Key Takeaways
- A moving average smooths out price into a single line, making the underlying trend easier to see through day-to-day noise.
- SMA (Simple Moving Average) weights every period equally; EMA (Exponential Moving Average) weights recent periods more heavily, so it reacts faster.
- Price trading above a rising moving average is typically read as bullish; price below a falling one is typically read as bearish.
- A shorter MA crossing above a longer MA is read as a bullish signal, and crossing below as bearish, though crossovers lag price and can whipsaw in a ranging market.
- You can overlay SMA 20, SMA 50 and EMA 20 on any chart in our free backtesting tool.
What a Moving Average Does
A moving average (MA) takes the average closing price over a fixed number of recent periods and plots it as a single smooth line, recalculating with each new bar so the line "moves" forward with price. The effect is to filter out short-term noise and leave a clearer picture of the underlying direction, which is why moving averages are the standard starting point for reading trend, the first of the three indicator categories covered in our technical analysis overview.
SMA vs EMA: What's the Difference?
Both moving average types answer the same basic question, "what's the average price been recently," but calculate it differently:
- Simple Moving Average (SMA): adds up the closing prices of the last N periods and divides by N, treating every period equally. An SMA 50 on a daily chart is simply the average close of the last 50 days, each day counting the same regardless of how recent it is.
- Exponential Moving Average (EMA): applies a mathematical weighting that gives more importance to recent prices, so it reacts faster to new information and hugs price more closely than an SMA of the same length.
Neither is strictly "better." SMA is smoother and generates fewer false signals in choppy conditions; EMA reacts sooner to genuine trend changes but is more prone to whipsaws. Many traders simply pick one style and stay consistent with it rather than switching back and forth.
Reading Trend From a Moving Average
The most basic use of a moving average is also the most reliable: look at where price sits relative to it, and which way it's sloping.
- Price above a rising MA: read as an uptrend. The MA itself is often watched as a zone of dynamic support, a level price pulls back toward and bounces from during a healthy trend.
- Price below a falling MA: read as a downtrend, with the MA acting as dynamic resistance on rallies.
- Price chopping around a flat MA: read as a range, no clear trend, generally the hardest and riskiest condition for trend-following tools to work in.
Moving Average Crossovers
A common signal is watching two moving averages of different lengths together, for example an SMA 20 and an SMA 50. When the shorter-period MA crosses above the longer-period MA, it's read as a bullish signal (sometimes called a "golden cross" when using longer periods like 50 and 200); when the shorter crosses below the longer, it's read bearish (a "death cross" with those same longer periods).
The tradeoff is lag: by the time two moving averages actually cross, a meaningful part of the price move has usually already happened. Crossovers work best in markets that are genuinely trending and tend to produce a string of false signals, called whipsaws, in sideways, range-bound conditions.
Practice Reading Moving Averages on Real Charts
You can add SMA 20, SMA 50 and EMA 20 directly onto any chart in our free backtesting and market replay tool, across 17 markets and 7 timeframes, and step bar by bar through real historical data to see exactly how price interacted with each line before and after major moves.
Frequently Asked Questions
What is the best moving average period to use?
There's no single correct answer; it depends on your timeframe and style. Shorter periods (10 to 20) react quickly and suit active, short-term trading; longer periods (50, 100, 200) move slowly and are more commonly used to judge the broader, longer-term trend.
Should I use SMA or EMA?
Both are valid and widely used. EMA suits traders who want faster signals and can tolerate more false positives; SMA suits traders who prefer smoother, more conservative readings. Many platforms, including our backtesting tool, offer both so you can compare them directly on the same chart.
Can moving averages predict future price?
No. A moving average is calculated entirely from past prices, so it always describes where price has been, not where it's going. It's a lagging indicator used to clarify the current trend, not a forecasting tool.
Why did a moving average crossover signal fail?
Crossovers are prone to whipsaws in range-bound or choppy markets, producing a cross, a quick reversal, and another cross in the opposite direction shortly after. This is why many traders only act on MA crossover signals that align with the broader trend and other confirming tools, as covered in our technical analysis overview.