What a moving average is
A moving average smooths out a jumpy price line by averaging the last few closing prices and plotting that average as a single line. A 5-day moving average plots the average of the last 5 closes at each point; a 20-day average uses the last 20. As each new day arrives, the window slides forward — which is why it's called moving. The result is a cleaner line that strips out day-to-day noise so the underlying direction is easier to see.
Why traders use them
Raw price is noisy — it zig-zags so much that the real trend is hard to read. A moving average filters that noise and answers a simple question at a glance: is price generally heading up, down, or sideways? When price is above a rising average, the trend is usually up; below a falling average, usually down. It turns a chaotic line into a readable trend.
Short versus long
The period (how many days you average) is a trade-off. A short average (like 5) reacts quickly and stays close to price, catching turns early — but it also reacts to noise and gives false signals. A long average (like 50 or 200) is smooth and reliable for the big trend, but it lags: by the time it turns, the move is well underway. Traders pick a period to match how fast they trade.
Crossovers and lag
Because a long average lags, traders watch for crossovers: when a short average crosses above a long one, it can signal momentum turning up (often called a golden cross); crossing below can signal it turning down (a death cross). Moving averages can also act as dynamic support or resistance — price often bounces off a rising average. But the lag means they confirm trends rather than predict them.
Toggle the short and long averages above until the lag-versus-noise trade-off is obvious — then take the quick check below.