Ask any crypto trader which indicator they use — RSI will be the most common answer.
Simple to understand. Easy to read. Powerful when used correctly. The Relative Strength Index has been a staple of technical analysis since J. Welles Wilder developed it in 1978.
RSI measures the speed and magnitude of recent price changes to evaluate whether an asset is overbought or oversold.
It is displayed as a single line oscillating between 0 and 100.
Calculation simplified:
RSI compares average gains to average losses over a specified period — typically 14 periods.
If price has been rising strongly — RSI moves toward 100.
If price has been falling strongly — RSI moves toward 0.
Overbought zone — RSI above 70:
Price has risen rapidly. Buyers may be exhausted.
Potential reversal or pullback ahead.
Do NOT automatically sell — price can remain overbought in strong uptrends.
Oversold zone — RSI below 30:
Price has fallen rapidly. Sellers may be exhausted.
Potential reversal or bounce ahead.
Do NOT automatically buy — price can remain oversold in strong downtrends.
Neutral zone — RSI between 30 and 70:
Normal market conditions.
No extreme reading.
Beginners see RSI above 70 and immediately sell. They see RSI below 30 and immediately buy.
This is wrong.
RSI can stay overbought for weeks in a strong uptrend.
Bitcoin during bull markets has maintained RSI above 70 for months while price continued rising dramatically.
RSI can stay oversold for weeks in a strong downtrend.
Selling short every time RSI goes oversold in a bear market results in buying into continued decline.
RSI overbought/oversold readings are warnings — not automatic trade signals. Always confirm with price action and trend context.
RSI in uptrends:
RSI tends to oscillate between 40 and 80.
Oversold in uptrend = RSI touching 40-50 area — not 30.
This is called the bullish range.
RSI in downtrends:
RSI tends to oscillate between 20 and 60.
Overbought in downtrend = RSI touching 50-60 area — not 70.
This is called the bearish range.
Understanding which range RSI is operating in tells you the dominant trend direction.
Like MACD — RSI divergence is one of the most reliable signals in technical analysis.
Bullish Divergence:
Price makes a lower low.
RSI makes a higher low.
Momentum not confirming price decline. Reversal likely upward.
Bearish Divergence:
Price makes a higher high.
RSI makes a lower high.
Momentum not confirming price rise. Reversal likely downward.
Trading RSI Divergence:
Most powerful divergence setups:
Beyond overbought/oversold — RSI level tells you about trend strength.
RSI above 50:
Bullish momentum dominant.
Buyers in control overall.
RSI below 50:
Bearish momentum dominant.
Sellers in control overall.
RSI crossing 50 from below:
Bullish signal — momentum shifting to buyers.
RSI crossing 50 from above:
Bearish signal — momentum shifting to sellers.
The 50 level is a simple but powerful filter — only take long trades when RSI is above 50 and short trades when below 50.
A lesser known but highly reliable RSI signal:
Bullish failure swing:
RSI falls below 30 → bounces above 30 → pulls back but stays above 30 → breaks above the previous bounce high.
This break above the previous RSI high is the entry signal.
Bearish failure swing:
RSI rises above 70 → falls below 70 → bounces but stays below 70 → breaks below the previous pullback low.
This break below the previous RSI low is the entry signal.
Default: 14 periods
The standard. Works on all timeframes. Start here.
Shorter periods — 7 or 9:
More sensitive. More signals. More false signals.
Used by short term traders.
Longer periods — 21 or 25:
Less sensitive. Fewer signals. More reliable.
Used by longer term traders.
RSI + Bollinger Bands:
Price at lower band + RSI below 30 = strong buy signal in ranging market.
Price at upper band + RSI above 70 = strong sell signal in ranging market.
RSI + Moving Average:
RSI above 50 + price above 200 MA = only take long trades.
RSI below 50 + price below 200 MA = only take short trades.
RSI + Support/Resistance:
RSI oversold at major support = highest probability long setup.
RSI overbought at major resistance = highest probability short setup.
In the next topic we will study the Stochastic Oscillator — a momentum indicator that works alongside RSI to provide stronger confirmation signals.