What is the RSI indicator and how do you use it?
RSI (Relative Strength Index) measures momentum on a scale of 0 to 100 by comparing recent gains with recent losses, usually over 14 periods. Above 70 is called overbought and below 30 oversold, but in a trend RSI can stay there for weeks. Swing traders use it to judge pullbacks and spot divergence.
- 1Turn on the divergence and compare the two lows in price with the two lows in RSI.
- 2Shorten the period to 7: RSI gets jumpier and touches the lines more often.
- 3Raise the overbought line to 80 and count how many signals disappear.
How RSI is calculated
RSI was created by J. Welles Wilder. It takes the average gain on up days and the average loss on down days over a period — 14 by default — and turns their ratio into a number between 0 and 100.
RSI = 100 − 100 ÷ (1 + average gain ÷ average loss)
If a stock rose on most of the last 14 days, RSI is high. If it fell on most of them, RSI is low. Around 50 means gains and losses roughly balance.
- Stock A: average gain / average loss
- ₹6 / ₹3, so the ratio is 2
- Stock A: RSI
- 100 − 100 ÷ (1 + 2) ≈ 66.7
- Stock B: average gain / average loss
- ₹2 / ₹6, so the ratio is about 0.33
- Stock B: RSI
- 100 − 100 ÷ 1.33 ≈ 25
Stock A's up days have been twice as strong as its down days, so RSI sits in the upper half. Stock B has been mostly falling, so RSI is near the bottom. Your charting platform does this sum for you every day.
Wilder's version smooths the averages, so each new day nudges RSI rather than resetting it. That's why RSI moves gradually instead of jumping around with every candle.
Overbought and oversold, without the myths
The classic levels are 70 and 30. The myth is that 70 means "sell" and 30 means "buy". In a strong uptrend, RSI can sit above 70 for a long time while price keeps rising. In a downtrend, it can stay below 30 while price keeps falling.
| RSI reading | In an uptrend | In a downtrend |
|---|---|---|
| Above 70 | Strong momentum — not a sell signal on its own | Rare; often a sharp bounce |
| 40 to 60 | Normal pullback zone | Normal bounce zone |
| Below 30 | Rare; the trend may be breaking | Weak momentum — not a buy signal on its own |
That's why many swing traders watch the middle of the range. In a healthy uptrend, pullbacks often hold RSI around 40–50, and momentum stays above 60 on the rallies.
RSI ranges: reading the trend from RSI itself
Over time, RSI tends to live in different bands depending on the trend. Many traders use these bands as a rough trend check. The numbers below are a common rule of thumb, not exact limits.
| Trend | Typical RSI band | What to watch |
|---|---|---|
| Uptrend | Roughly 40 to 80 | Dips holding near 40–50 are normal pullbacks |
| Sideways | Roughly 35 to 65 | Turns near the edges line up with the range |
| Downtrend | Roughly 20 to 60 | Rallies failing near 55–60 show sellers still in charge |
A range shift is when RSI stops behaving like one band and starts behaving like another. If a stock in a downtrend suddenly pushes RSI above 65 and then holds above 40 on the next dip, momentum may be turning — worth watching alongside the price structure.
RSI divergence
A bullish divergence is when price makes a lower low but RSI makes a higher low. Price fell further, but with less force behind it. A bearish divergence is the mirror: a higher high in price with a lower high in RSI.
Turn on the divergence in the lab above to see one drawn on the practice chart. Divergence is a warning that momentum is changing, not a trigger. It works best at support or a demand zone, confirmed by a strong candle.
Divergence can repeat two or three times before price turns. Wait for price itself to confirm.
A simple way to confirm a bullish divergence: wait for price to close above the high of the candle that made the second low. Put the stop under that second low. If the divergence was real, price shouldn't come back there; if it does, the idea was wrong and the loss is small.
Settings for swing trading
Fourteen on the daily chart is the standard and a sensible place to start. A shorter period, like 7, makes RSI jumpier and reach the extremes more often. A longer period, like 21, smooths it out and makes extremes rarer.
Move the period slider in the lab and watch the line change. Changing settings doesn't create an edge — it changes how often the line touches your levels. Pick one setting and learn how it behaves.
Using RSI in a planned trade
- Trend
- Price above a rising 50 EMA
- Pullback
- Price dips to support at ₹600; RSI holds at 44
- Entry
- ₹612, as RSI turns back above 50
- Stop-loss
- ₹590, below support
- Shares
- Risk ₹1,100 ÷ ₹22 a share = 50 shares
RSI helped judge that the pullback was orderly. Support set the stop, and the stop set the size — see the position size calculator.
Notice what RSI didn't do: it didn't pick the stock, set the stop or decide the size. It answered one question — is this pullback orderly or a collapse? — and the rest came from the chart and the plan.
An RSI checklist for pullbacks
- 1Confirm the trend first with price and the 20 and 50 EMA. RSI is a second opinion, not the first.
- 2Wait for a pullback toward support or the 20 EMA.
- 3Check RSI holds roughly in the 40–50 area. A fall below 30 in an uptrend is a warning, not a bargain.
- 4Look for RSI to turn up with a strong candle and better volume.
- 5Place the stop below the pullback's low and work out the shares from it.
- 6Check there's room to the next resistance for at least about 1 : 2.
Common RSI mistakes
- Selling a strong stock because RSI is above 70. Strong trends stay overbought.
- Catching falling stocks because RSI is below 30. Oversold can get more oversold.
- Treating every divergence as a reversal. Divergences often repeat before price turns, and some never lead anywhere.
- Using RSI alone. Without support, resistance and a stop, an RSI reading is just a number.
- Switching timeframes until RSI agrees with you. Decide the timeframe before you look.
Quick check
Key terms
- RSI
- Relative Strength Index: a 0–100 momentum gauge comparing average gains with average losses.
- Overbought
- RSI above 70 by convention — strong recent buying, not automatically a reason to sell.
- Oversold
- RSI below 30 by convention — strong recent selling, not automatically a reason to buy.
- Divergence
- When price and RSI move in opposite directions at a high or low, hinting that momentum is changing.
Common questions
What is the best RSI setting for swing trading?
The default of 14 on the daily chart is a sound choice. Shorter settings react faster but give more false extremes.
What does RSI above 60 mean?
Many traders read RSI holding above 60 as a sign of strong momentum. It's a filter for trend strength, not a signal to buy on its own.
Should I buy when RSI is below 30?
Not on that alone. In a downtrend RSI can stay below 30 while price keeps falling. Look for support, a divergence and a confirming candle.
Is RSI better than MACD?
They measure momentum differently. RSI shows how strong recent moves are; MACD shows how two moving averages relate. Most traders use one, not both.
Which timeframe is best for RSI in swing trading?
The daily chart is the usual choice for swing trades held for days or weeks. Some traders check weekly RSI for the bigger trend. Intraday RSI gives many signals that don't matter for a multi-day trade.
What does an RSI cross above 50 mean?
It means average gains have overtaken average losses over the period. Some traders use it as a sign momentum has turned up after a pullback. It works better with support and a confirming candle.
What is hidden divergence in RSI?
In an uptrend, price makes a higher low while RSI makes a lower low. Some traders read it as the trend likely continuing. Like regular divergence, it's a hint to look closer, not a trigger.
RSI indicator kya hota hai?
RSI ek momentum indicator hai jo 0 se 100 ke beech chalta hai. 70 ke upar overbought aur 30 ke neeche oversold maana jaata hai, lekin trend mein RSI wahan lambe samay tak reh sakta hai.
Keep going
Education only — not investment advice. Trading in the stock market carries risk. Charts on this page use made-up prices for practice — they are not real stocks or recommendations. Examples are for learning only.