The math behind it
For a 21 EMA, k = 0.0909, so today's close carries about 9% of the weight. For a 200 EMA, k is about 1%, which is why it moves so slowly.
An example with numbers
A 21 EMA reads 100.00 yesterday. Today closes at 103.30.
A 3.3 point jump in price moves the EMA by 0.3. A 21-period SMA moves by (today's close − the close that drops out of the window) ÷ 21, so it can lurch when an old extreme bar leaves. The EMA never drops a bar suddenly, it just lets old prices fade.
Mistakes to avoid
- Trading every crossover. In a range, EMA crosses fire constantly and most fail.
- Expecting identical values everywhere. Different seeds and data start points shift EMAs slightly between platforms.
- Treating it as an exact line. Price reacts around an EMA, not to the tick.
What the journal does with it
The backtester chart has an Indicators panel with EMA, SMA, WMA, Bollinger and RSI overlays. You set the period and colour of each, and they are computed live from the candles without revealing future bars. Tag your EMA setups and the journal's per-setup stats show whether they actually pay.
See your own EMA from real trades
Stop estimating it in a spreadsheet. Log or sync your trades and the journal keeps the number current after every close.
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