EMA (Exponential Moving Average)
The exponential moving average weights recent closes more heavily than old ones, so it tracks a turn in price sooner than a simple average of the same period.
The EMA applies an exponential decay to the closes. Each new bar gets a fixed fraction of the weight and every older bar's influence shrinks geometrically. A 21-day EMA therefore responds to this week's prices far more than to prices from a month ago, where a 21-day SMA treats them identically. PatternsRadar seeds each EMA from the SMA of its period, the textbook initialisation, which keeps the early values honest.
On daily NSE bars the common setup is a pair. The 9 or 21-day EMA is the fast line a swing trader wants price to hold; the 50 or 200-day sits behind it as the regime filter. Pullback buyers screen for price returning to a rising 21-day EMA inside an uptrend. Trend followers ask whether price has held above the 50 for weeks rather than days, which is a question about persistence.
The cost of responsiveness is false starts. Because the EMA turns with recent price it also turns with recent noise, and in a rangebound stock a short EMA is crossed constantly, each cross looking like the last one that worked. The lag is reduced and never removed. An EMA is still an average of the past, and no weighting scheme makes an average predictive.
Against the SMA, the choice trades smoothness for speed. The two 200-day lines rarely disagree by much. The two 9-day lines disagree constantly, and that is where the choice matters. Traders who act on short-period crosses tend to prefer the EMA because it front-loads the recent evidence, which is also why it hands them more signals to be wrong about.
In Sift
Written as ema(21) — precomputed at 9, 21, 50, 200. A working scan — stocks holding above a 21-day EMA that itself sits above the 50, an uptrend at two speeds:
where close > ema(21) and ema(21) > ema(50)1
of the 500 most-traded NSE stocks match today, as of 25 Sept 2026
Scans that use it
Prebuilt scans in the library whose query reads this value — each with a hit-rate replay over the last 250 sessions.
Within 3% of the 52-week high
Within 3% of the yearly high and above the 50-day EMA. Plenty of traders prefer this to the breakout candle itself.
9/21 EMA crossover
The 9-day EMA crossing above the 21 within the last two sessions, in a stock still above its 200-day. A golden cross on a swing trader's clock.
Longest streaks above the 21 EMA
Twenty or more consecutive closes above the 21-day EMA, longest streak first.
Common questions
What period EMA should I use?
Whichever matches the holding period you are timing. The 9 and 21-day EMAs are swing-trading lines that price should hold in a strong trend; the 50-day is the intermediate filter and the 200-day the long-term regime. Shorter is faster and noisier, and there is no free responsiveness. The replay on each scan page compares periods on actual history rather than folklore.
Why does the EMA react faster than the SMA?
Weighting. The SMA gives every bar in its window an equal vote. The EMA gives the newest bar the largest vote and shrinks each older bar's geometrically, so when price turns, the newest bars carry the news and the EMA bends first. The same property makes it more responsive to noise.