Suppose you wanted to know whether you've been getting taller. You don't measure yourself once and decide. You measure every month, and you look at the trend over several months. One bad reading on a day you slouched doesn't mean you shrank.
A moving average does the same thing for a price chart. Instead of reacting to every single up-and-down tick, it smooths the noise and shows you the underlying trend.
How it's built
The math is honestly trivial. To compute a 20-day Simple Moving Average (SMA20):
- Take the closing price for each of the last 20 days.
- Add them all up.
- Divide by 20.
That number is today's SMA20. Tomorrow you'll drop the oldest day, add tomorrow's close, and divide again. The line "moves" with each new candle — hence the name.
The three lines traders watch
You almost always see the same three on a chart:
- SMA20 — short-term trend. Reacts within days. Useful for swing trading.
- SMA50 — medium-term trend. Reacts within weeks. The line institutional traders watch most.
- SMA200 — long-term trend. Reacts within months. The line the entire investment world uses to decide "bull market or bear market".
The longer the average, the slower it moves. SMA200 barely budges from day to day; SMA20 wiggles around with the price.
What "price below SMA" actually tells you
If today's gold price is below SMA50, it means today's price is lower than the average price of the last 50 days. That's a sign that recent days have been weaker than the period before — usually a soft bearish signal in itself.
If price is below SMA200, it means today's price is lower than the average price of the last 200 days. That's much heavier. The entire market often treats SMA200 as the dividing line between "bull market" and "bear market".
Crossovers
When a faster moving average crosses a slower one, traders pay attention. Two famous examples:
- Golden Cross — SMA50 crosses ABOVE SMA200. Read as a major bullish signal: the medium-term trend has turned up enough to overtake the long-term trend.
- Death Cross — SMA50 crosses BELOW SMA200. Read as a major bearish signal: medium-term momentum has rolled over.
These crossovers are slow. By the time the lines cross, the underlying move is already weeks or months along. They're confirmation tools, not entry signals — but they're the kind of signal that gets a headline in financial press because they don't happen often.
Moving averages don't predict the future. They describe the past in a way that's easier to read. The signal isn't magic — it's the fact that hundreds of millions of dollars of algorithmic strategies all watch the same lines.
Common patterns
- Price riding above SMA20 — short-term uptrend, momentum is healthy.
- Pullback to SMA50 — price drops to its medium-term average. Often a buying opportunity in an established uptrend.
- SMA50 acting as resistance from below — price tries to break back above SMA50 and fails. Bearish.
- Price below all three — strong downtrend; only counter-trend traders touch it.
- Price above all three, SMAs stacked 20 > 50 > 200 — textbook bullish alignment.
For a gold watcher
If you look at one gold chart a day, drop SMA20, SMA50, and SMA200 onto it and check three things: is price above or below each line, are the lines stacked in order, and is the price respecting any of them as support or resistance? Those three questions answer 80% of "what's the trend?" before you've touched a single fancy indicator.