What Is RSI?
The Relative Strength Index (RSI) is a momentum oscillator that measures the speed and magnitude of recent price changes on a scale of 0 to 100. Developed by J. Welles Wilder Jr. in his seminal 1978 book New Concepts in Technical Trading Systems, RSI has become one of the most widely used technical indicators in both traditional finance and cryptocurrency markets.
RSI helps traders identify whether an asset is potentially overbought or oversold, providing actionable signals for entry and exit points. In the highly volatile crypto market, RSI is an essential tool for making data-driven trading decisions.
How RSI Is Calculated
The RSI formula uses average gains and average losses over a specified period (typically 14 periods):
RSI = 100 - (100 / (1 + RS))
Where RS (Relative Strength) = Average Gain / Average Loss over the lookback period.
Here's the step-by-step process:
- Calculate price changes for each period
- Separate gains and losses
- Calculate the average gain and average loss over 14 periods
- Compute RS = Average Gain / Average Loss
- Apply the RSI formula
The result is a number between 0 and 100. Higher values indicate stronger upward momentum, while lower values indicate stronger downward momentum.
Reading RSI Signals
Traditional Thresholds
- Above 70: The asset is considered overbought — price may be due for a pullback or correction
- Below 30: The asset is considered oversold — price may be due for a bounce or reversal
Crypto-Adjusted Thresholds
Cryptocurrency markets are significantly more volatile than traditional markets. Many experienced crypto traders adjust their thresholds:
- Above 80: Overbought in crypto (instead of 70)
- Below 20: Oversold in crypto (instead of 30)
This adjustment accounts for the fact that crypto assets can remain in "overbought" or "oversold" territory for extended periods during strong trends.
The Centerline (50)
The RSI 50 level acts as a trend indicator:
- RSI consistently above 50: Bullish momentum dominates
- RSI consistently below 50: Bearish momentum dominates
- RSI hovering around 50: Market is in consolidation/indecision
Key RSI Trading Strategies
1. Overbought/Oversold Strategy
The most straightforward approach:
- Buy signal: RSI drops below 30 (or 20 for crypto), then crosses back above
- Sell signal: RSI rises above 70 (or 80 for crypto), then crosses back below
Important: Don't sell just because RSI is above 70. In strong bull trends, RSI can stay overbought for weeks. Wait for the crossback confirmation.
2. RSI Divergence
Divergence occurs when price and RSI move in opposite directions, often signaling a potential reversal:
Bullish Divergence: Price makes a lower low, but RSI makes a higher low → potential upward reversal
Bearish Divergence: Price makes a higher high, but RSI makes a lower high → potential downward reversal
Divergence is one of the most powerful RSI signals, but it requires patience — the reversal may not happen immediately.
3. Centerline Crossover
- Bullish signal: RSI crosses above 50 from below
- Bearish signal: RSI crosses below 50 from above
This strategy works best as a trend-confirmation tool rather than a standalone signal.
4. RSI + Moving Average Combination
Combining RSI with a 200-period moving average creates a robust system:
- Buy: Price is above the 200 MA AND RSI is below 30 (oversold pullback in an uptrend)
- Sell: Price is below the 200 MA AND RSI is above 70 (overbought bounce in a downtrend)
This combination filters out many false signals by aligning RSI with the broader trend.
RSI in Crypto vs. Traditional Markets
Several factors make RSI behave differently in crypto:
- 24/7 Trading: Unlike stock markets, crypto never closes. RSI signals can form at any time, including weekends.
- Higher Volatility: Crypto assets regularly see 10-20% moves in a single day. Standard RSI thresholds may need adjustment.
- Lower Liquidity: Smaller altcoins can produce more extreme RSI readings due to thinner order books.
- Sentiment-Driven: Crypto markets are heavily influenced by social media sentiment, making RSI divergences particularly valuable for spotting exhaustion points.
Common RSI Mistakes
Using RSI in Isolation
RSI should never be your only indicator. Combine it with volume analysis, support/resistance levels, and other indicators like MACD or Bollinger Bands for confirmation.
Ignoring the Trend
Selling an asset simply because RSI is above 70 during a strong bull market is a common mistake. In trending markets, RSI can remain overbought or oversold for extended periods. Always consider the broader trend before acting on RSI signals.
Wrong Timeframe
RSI on a 5-minute chart produces many more signals (and false positives) than RSI on a daily chart. For swing trading, use the daily or 4-hour timeframe. For day trading, combine the hourly RSI with a higher timeframe trend filter.
Not Waiting for Confirmation
Acting on RSI entering overbought/oversold territory without waiting for it to cross back leads to premature entries. Always wait for the crossback confirmation.
Conclusion
RSI is a powerful, versatile indicator that belongs in every crypto trader's toolkit. Its ability to identify overbought and oversold conditions, spot divergences, and confirm trends makes it invaluable for data-driven trading decisions.
However, no single indicator is perfect. The most successful traders combine RSI with other technical analysis tools, proper risk management, and a disciplined trading plan. Tools like Crypto Analysis AI incorporate RSI alongside 100+ other technical indicators to provide comprehensive, multi-timeframe analysis — helping you make more informed decisions in the fast-moving crypto market.