What Is a Moving Average? (Day Trading Glossary)

A moving average is a technical indicator that smooths out a stock's price over a set number of periods to show the underlying trend. It's called "moving" because it updates every period: the oldest price drops off and the newest price is added, so the line moves along with price.

In plain terms, it takes the noise out of a jumpy chart and shows you which way the stock is leaning.

How a moving average works

You pick a length, say 20 periods, and the indicator averages the closing prices over those 20 periods. On the next candle, it drops the oldest price, adds the newest, and recalculates. Plotted on a chart, that string of averages becomes a smooth line under or over price.

A shorter length (like 9 or 20) hugs price closely and reacts fast. A longer length (like 50 or 200) is slower and smoother, and it shows the bigger trend.

SMA vs EMA

There are two common types, and the difference is simple.

A simple moving average (SMA) weights every period equally. It adds up the closing prices and divides by the number of periods.

An exponential moving average (EMA) gives more weight to recent prices, so it reacts faster to a fresh move than an SMA of the same length. Most active day traders lean on the EMA for that reason, because in fast intraday trading you want the line to keep up with price.

How traders use moving averages

Moving averages help you read a chart in a few ways.

Trend direction. A rising average points to an uptrend, a falling one points to a downtrend. Price holding above the average is a sign of strength. Price breaking below it is a sign of weakness.

Dynamic support and resistance. A moving average often acts like a moving floor that a pulling-back stock bounces off, or a ceiling it struggles to push through.

Crossovers. When a faster average crosses a slower one, traders read it as a shift. A "golden cross" is when a short-term average crosses above a long-term one (often the 50-day above the 200-day), read as bullish. A "death cross" is the opposite and is read as bearish. These are slower, longer-term signals, not intraday ones.

How I use moving averages

Here's the day-trading version I actually use, which is different from the 50-day and 200-day stuff you'll read elsewhere.

I trade on the 1 to 5-minute chart, so I use fast EMAs, mainly the 9 and the 20, to read the short-term trend. I only want to be long on the "front side," which means price is above those EMAs and the 9 is above the 20. The moment the 9 crosses below the 20, the front side is over and I step away.

I also lean on the 90 EMA, along with VWAP, as the line I risk against. When I take an entry near the 90 EMA, my stop sits just under it, often only a cent or two away, so my risk is tiny and defined. That's the whole idea behind my method: the moving average isn't a magic buy signal, it's a reference line that tells me which side to be on and where to get out.

Frequently asked questions

What is a good moving average for day trading?

There's no single best number. Day traders usually use fast exponential moving averages like the 9 and 20 for the short-term trend on intraday charts, plus a slower one like the 90 EMA to lean on for risk. Longer averages like the 50 and 200 are more for swing and position traders. The right one depends on your timeframe.

Is an SMA or EMA better?

Neither is better in the abstract. An EMA reacts faster because it weights recent prices, which most day traders prefer for quick intraday moves. An SMA is smoother and slower, which some longer-term traders like for filtering out noise. It's a speed-versus-smoothness trade-off.

What is a golden cross?

It's the name for one particular crossover: a shorter average rising above a longer one, classically the 50-day over the 200-day. Traders treat it as an optimistic, longer-term sign. The reverse setup, a shorter average dropping below a longer one, is the "death cross," read as pessimistic.

This content is for educational purposes only and is not financial advice. Trading involves significant risk and may not be suitable for all traders.