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Technical Analysis

RSI — relative strength index

What RSI measures, why "above 70 means sell" destroys accounts, and the two ways professionals actually use it.

Technical AnalysisIntermediate11 min read
Browse Technical Analysis(172)

RSI is probably the most widely used oscillator in the world and almost certainly the most widely misused. Understanding what it actually calculates dissolves most of the confusion immediately.

RSI = 100 − 100 / (1 + RS) where RS = average gain ÷ average loss
Average gain
Smoothed average of up-day moves over the period, usually 14
Average loss
Smoothed average of down-day moves over the same period

Example: If over 14 sessions the average up move is ₹6 and the average down move is ₹2, RS = 3 and RSI = 100 − 100/4 = 75. All that tells you is that up moves have been three times the size of down moves. It says nothing about value.

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What "overbought" does and does not mean

The logic is worth being explicit about. RSI is a momentum measure, so extreme readings indicate strong momentum. Strong momentum is a characteristic of the beginning and middle of trends, not just their ends. The strongest stocks spend most of their time "overbought" — that is what being the strongest stock looks like numerically.

The range-shift technique

This is the single most useful thing to know about RSI, and it is rarely taught. RSI does not oscillate around 50 regardless of conditions — the range it occupies shifts with the trend.

Market conditionRSI typically rangesWhat that means practically
Strong uptrendRoughly 40 to 90Pullbacks bottom near 40–50, not 30. Waiting for RSI 30 means never buying.
Strong downtrendRoughly 10 to 60Bounces top out near 55–60, not 70. That is where to consider exits.
Range-boundRoughly 30 to 70The textbook behaviour — and the only regime where classic overbought/oversold rules work.

Divergence

Divergence is the second legitimate use. It occurs when price and RSI disagree about the strength of a move.

  • Bearish divergence — price makes a higher high, RSI makes a lower high. The new high was achieved with less momentum than the previous one. Buyers are working harder for less.
  • Bullish divergence — price makes a lower low, RSI makes a higher low. The new low came with less selling force. Sellers are running out.

Period selection

14 is the default because Welles Wilder chose it in 1978, not because it is optimal. Shorter periods (7, 9) produce more signals and far more noise; longer periods (21, 25) produce fewer, steadier signals. If you shorten the period, you must widen the thresholds — a 7-period RSI hits 70 and 30 constantly.

Check yourself

A stock in a strong uptrend has RSI at 78. Its previous three pullbacks each bottomed with RSI around 45. What is the sensible interpretation?

Simple bhasha mein
Bahut tez bhaaga hua banda

Koi 2 km lagataar sprint kar le toh thakega hi — par iska matlab nahi ki woh abhi girega. RSI 70 ke upar matlab stock bina saans liye bhaaga hai. Strong trend mein woh hafton tak 70 ke upar reh sakta hai. RSI "bech do" ka signal nahi, "saans dekh lo" ka ishaara hai.

What to remember
  • RSI measures how one-sided recent moves have been — nothing about value.
  • Overbought means strong. In an uptrend, RSI can stay above 70 for months.
  • RSI ranges shift with the trend: 40–90 in uptrends, 10–60 in downtrends, 30–70 in ranges.
  • Classic overbought/oversold rules only work in range-bound markets.
  • Divergence is a warning to manage risk, not a signal to reverse position.
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Common questions

Short, direct answers to what people ask about this topic.

rsi meaning in stock market
RSI, the relative strength index, is a momentum oscillator that compares the average size of up moves with the average size of down moves over a set period and plots the result on a 0 to 100 scale. A reading of 75 simply means up moves have recently been about three times the size of down moves. It measures how one-sided price action has been, and says nothing about whether a stock is cheap or expensive.
the default period used for the relative strength index is
14. Welles Wilder used it when he introduced the indicator in 1978 and it became the standard setting on charting platforms, not because it is mathematically optimal. Shorter settings such as 7 or 9 fire far more often and far more noisily; longer settings such as 21 or 25 give fewer, steadier readings. If you shorten the period you have to widen the thresholds, because a 7-period RSI reaches 70 and 30 constantly.
does rsi above 70 mean the stock is a sell
No — an RSI above 70 on its own is not a sell signal. It means recent moves have been strongly one-sided, which describes powerful momentum rather than an expensive price, and momentum like that is characteristic of the beginning and middle of trends as much as their ends. In a strong uptrend RSI can stay above 70 for months, and the classic overbought and oversold rules only behave the textbook way in range-bound markets.
what rsi level do pullbacks stop at in an uptrend
Usually around 40 to 50 in an established uptrend, not 30. The whole RSI range shifts with the trend: roughly 40 to 90 in strong uptrends, roughly 10 to 60 in strong downtrends, and roughly 30 to 70 only when the market is ranging. Waiting for RSI 30 in a genuine uptrend generally means never buying at all, and the first pullback that breaks below 40 is the reading that says the trend has changed character.
rsi divergence meaning
RSI divergence is when price and RSI disagree about the strength of a move — price makes a higher high while RSI makes a lower high (bearish), or price makes a lower low while RSI makes a higher low (bullish). It says the latest push carried less force than the one before it. Divergence is a warning to manage risk rather than a trigger to reverse, because in a strong trend it can persist for weeks while price keeps going.