Crypto Traders Misunderstand the Relative Strength Index

The Relative Strength Index (RSI) is a widely used momentum oscillator in crypto trading. However, many traders misinterpret what it actually measures. Instead of using RSI as a simple overbought/oversold indicator, it's essential to understand its underlying calculation.

The standard RSI calculation compares the average size of recent up moves to the average size of recent down moves over a defined lookback period. This produces a bounded oscillator that responds to the magnitude and consistency of directional moves, not price levels. In other words, RSI measures buying or selling pressure rather than absolute price direction.

This distinction is crucial because strong trends can keep RSI elevated or depressed for extended periods. For instance, Bitcoin spent weeks with its daily RSI above 65 in late 2024 and early 2025. Traders who sold every time the RSI crossed 70 would have exited positions that continued climbing.

To use RSI effectively, traders should pair it with trend context, volume confirmation, and appropriate timeframes. The conventional interpretation of RSI is straightforward: readings above 70 signal overbought conditions, while readings below 30 indicate oversold conditions. However, this approach can be problematic in strong uptrends or downtrends.

RSI divergence, where price and RSI move in opposite directions, can signal weakening momentum. There are two types of divergences: bullish and bearish. Bullish divergence appears when price makes a lower low but RSI makes a higher low, suggesting that selling pressure is weakening even though price is still declining. Bearish divergence occurs when price makes a higher high but RSI makes a lower high, indicating that buying momentum is fading even as price pushes higher.