Series: Learn Trading — Day 3 of 24
In Day 2, we drew trend lines by hand. Today we let math do the work. Moving averages are probably the most widely used indicator in trading — and for good reason. They smooth out price noise and make trends visible at a glance.
What Is a Moving Average?
A moving average takes the closing prices of the last N days (or candles) and averages them. As each new day comes in, the oldest day drops off. The result is a smooth line that trails the price.
Think of it like this: if you track Nifty’s closing price every day and keep a running average of the last 20 days, you get the 20-day moving average. It won’t react to a single wild day — it shows you the general direction.
Simple Moving Average (SMA)
The SMA is straightforward. Add up the last N closing prices, divide by N.
Example: Say Reliance closed at ₹2,400, ₹2,420, ₹2,410, ₹2,450, and ₹2,440 over the last 5 days.
5-day SMA = (2400 + 2420 + 2410 + 2450 + 2440) / 5 = ₹2,424
Tomorrow, when a new closing price comes in, the oldest one (₹2,400) drops out and the new one takes its place. The average “moves” forward — hence the name.
Common SMA periods:
- 20-day SMA — short-term trend (roughly one month of trading)
- 50-day SMA — medium-term trend
- 200-day SMA — long-term trend (the big one institutional traders watch)
Exponential Moving Average (EMA)
The SMA has a problem: it treats every day equally. The price from 50 days ago carries the same weight as yesterday’s price. That feels wrong — recent prices should matter more.
The EMA fixes this by giving more weight to recent prices. The math involves a multiplier (2 / (N + 1)), but you don’t need to calculate it by hand — every charting platform on Sahi or anywhere else computes it for you.
What matters: The EMA reacts faster to price changes than the SMA. When TCS gaps up 3% on earnings, the EMA catches up quicker. The SMA takes its time.
When to use which?
- SMA — better for identifying long-term trends, less noise
- EMA — better for short-term trading, faster signals
Most traders use both. A 200-day SMA for the big picture, a 9 or 21-day EMA for entries and exits.
How Traders Use Moving Averages
1. Trend Direction
This is the simplest use. If the price is above the 200-day SMA, the stock is in an uptrend. Below it? Downtrend.
Pull up Nifty 50 on any chart. When Nifty trades above its 200-day SMA, the market is broadly bullish. When it dips below, sentiment turns cautious. Fund managers actually track this — it’s not just retail trader stuff.
2. Support and Resistance
Moving averages act as dynamic support and resistance levels. In an uptrend, prices often bounce off the 50-day or 200-day SMA. Traders place buy orders near these levels because they expect the bounce.
Real example: Watch how Nifty behaves around its 20-day EMA during a trending market. During the 2023-24 bull run, the index repeatedly bounced off the 20 EMA on the daily chart. Traders who bought those dips did well.
3. Crossovers
This is where it gets interesting. When a shorter moving average crosses above a longer one, it’s a bullish signal. When it crosses below, bearish.
Golden Cross: 50-day SMA crosses above the 200-day SMA. Traders see this as a strong bullish signal. It doesn’t happen often, which is why people pay attention when it does.
Death Cross: 50-day SMA crosses below the 200-day SMA. The ominous name matches the sentiment — it signals potential trouble ahead.
Faster crossover: The 9 EMA crossing the 21 EMA is popular among swing traders on NSE. It gives more frequent signals than the golden/death cross — more trades, but also more false signals.
4. The Moving Average Envelope
Some traders plot bands at a fixed percentage above and below a moving average (say ±2% from the 20-day SMA). When price touches the upper band, it’s potentially overbought. Lower band? Potentially oversold. We’ll cover a more sophisticated version of this — Bollinger Bands — on Day 7.
Practical Tips for Indian Markets
Start with these three on your chart:
- 200-day SMA (long-term trend)
- 50-day SMA (medium-term)
- 21-day EMA (short-term entries)
Open Sahi, pull up any Nifty 50 stock, and add these three. You’ll immediately see the trend structure.
Don’t use moving averages alone. A golden cross on a low-volume stock doesn’t mean much. Combine with volume (Day 4) and RSI (Day 5) for better signals.
Timeframe matters. A 20-day SMA on a daily chart is very different from a 20-period SMA on a 15-minute chart. If you’re swing trading, stick to daily charts. Intraday traders use 5-minute or 15-minute candles with shorter MAs.
Sideways markets kill moving averages. When Nifty is chopping around in a 200-point range, moving averages will whipsaw you with false signals constantly. MAs work best in trending markets. If the market is flat, step back and wait.
Quick Recap
| Concept | What It Does |
|---|---|
| SMA | Equal-weight average of last N prices — smooth, slow |
| EMA | Recent-weight average — faster reaction |
| Price above MA | Bullish bias |
| Price below MA | Bearish bias |
| Golden Cross | 50 SMA crosses above 200 SMA — bullish |
| Death Cross | 50 SMA crosses below 200 SMA — bearish |
What’s Next
Moving averages tell you about trend and momentum, but they say nothing about how much trading is happening. Tomorrow in Day 4, we look at Volume Analysis — the fuel behind every price move. A breakout without volume is just noise.
See you then.