What the line measures
A moving average summarizes a selected window of prices. A simple average weights observations equally; an exponential average emphasizes recent observations. Neither has access to future prices.
Choose a frame of reference
The length counts chart bars, not necessarily days. Record the timeframe and price input before comparing two lines. A shorter window responds faster, but can make brief fluctuations look more important.
Read context, not instructions
Slope and crossovers describe the chosen price history. They do not establish that a move will continue. Repeated crossings in sideways conditions can produce conflicting interpretations.
Try a controlled comparison
On a practice chart, hold the symbol and timeframe fixed and change only the average length. Write down what becomes clearer and what arrives later. Avoid choosing settings only because one past move looks convincing.
Worked example: a 5-period SMA and EMA
For invented closes of 100, 102, 101, 103 and 109, the 5-period SMA is 515 divided by 5, or 103. A conventional 5-period EMA uses a weight of 2/(5+1), or one third. Assuming the preceding EMA is 102, the new EMA is 102 + (109−102)/3, about 104.33. That preceding EMA is a separate illustrative assumption. Greater sensitivity to the latest price does not establish better prediction or returns. These are calculation examples, not actual market results.
Why do two moving averages disagree?
First match the symbol, exchange, candle type, trading session, timeframe, price source and length. A 20-bar average on a 4-hour chart does not use the same observations as a 20-bar daily average. Equal lengths also differ when one line uses SMA and the other EMA. Save a layout, change only one input, and compare closed candles in both a rising and a sideways interval. Keep examples where the tool is less useful. A crossover describes the relative order of averages; it does not guarantee an execution price or establish a universally best setting.
Official references
Source pages may be in English.