An average of the last N closes — so it always lags.
- The lag is the mechanism, not a flaw to tune away
- Crossovers whipsaw in sideways markets
- Every average points the wrong way at every major turn
What this is about
A moving average is the average closing price over the last N periods, redrawn each period. It is the simplest indicator there is, the foundation of several others, and the one most likely to be used as a rule when it should be used as context.
How it is built
A 50-day moving average on today's chart is the average of the last 50 closes. Tomorrow it drops the oldest close and adds the newest. Plotted over time it becomes a line that follows the price with a lag.
The lag is not a flaw — it is the entire mechanism. Smoothing means responding late. An average that reacted instantly would just be the price again, and would tell you nothing the price did not.
That gives you the only real dial: length.
- Short (5, 10, 20) — follows closely, turns quickly, and changes direction on noise.
- Long (150, 200) — slow, steady, and still pointing the old way well after a genuine turn.
There is no correct length. A shorter one gives earlier signals and more false ones; a longer one gives fewer and later. That is a trade, not a solved problem, and anybody presenting a specific number as optimal is describing a period they tested it on.
What it is genuinely good for
Direction at a glance. Is the line rising, falling or flat? On a noisy chart this is a real question and the average answers it honestly.
Distance from normal. Price far above its own long average has moved a long way, quickly, relative to its recent history. That is a fact worth noticing, and it says nothing about what happens next.
A reference everybody shares. The 50 and the 200 are watched widely enough that they function partly as a self-fulfilling reference point — people act at those levels because other people act at those levels. That is a real effect and a thin one; it is a crowd, not a law.
Crossovers, and the honest position
When a shorter average crosses above a longer one, it is called a golden cross; below, a death cross. Both names oversell dramatically.
What a crossover actually is: arithmetic confirming that recent prices have been higher than older prices for long enough to drag the short average through the long one. It is a restatement of what already happened, arriving late by construction.
How it tests: results are mixed and highly dependent on market, period and the lengths chosen. Backtests of the 50/200 crossover on major indices sometimes show it avoiding part of a large drawdown — and also show it generating whipsaws in sideways markets, each with a cost. The strategy's main documented benefit is usually reduced drawdown, not higher returns.
Where it clearly fails: sideways markets. Price oscillating around its own average produces crossover after crossover, each one a trade, each with a spread and possibly a commission. See How fees and spread compound for what a sequence of small costs does.
A crossover is worth knowing because it will be mentioned. It is not a system.
What this does not tell you
It does not tell you the trend will continue. It tells you what the average has done. Every moving average points confidently in the wrong direction at every major turn — necessarily, because it is made of the past.
It does not tell you the average is support. "It bounced off the 200-day" is said constantly. Sometimes it bounces; sometimes it goes straight through and the same people say it "broke". A level that explains both outcomes afterwards predicted neither.
It does not tell you which length to use. See above. If you find yourself trying lengths until one would have worked on the chart in front of you, you are fitting, and it will not survive contact with the next chart.
It does not know about gaps or events. An average is arithmetic on closes. It has no idea results are tomorrow.
Where to see this in the app
Chart → the moving-average controls let you lay 5, 10, 50, 150 and 200-day averages over the price, together or separately. The experiment worth doing first: put the 50 and the 200 on the same chart and simply watch how far behind the price they both are at the turns.
Chart → Technicals summarises where price sits relative to its averages, alongside RSI and MACD — as a reading, not a recommendation.
Alerts can tell you when price reaches a level, which is the practical way to use an average without watching a screen: set the alert, then decide.
Note that these are simple averages. Exponential averages, which weight recent prices more heavily, are used inside MACD but are not yet offered as a line of their own.