Recently, while organizing my trading notes, I realized that many people still have a superficial understanding of the RSI indicator. In fact, its logic isn't as complicated as it seems.

RSI stands for Relative Strength Index, and its core concept is to measure the strength of upward and downward momentum over a certain period using values from 0 to 100. Simply put, if recent upward momentum dominates, the value climbs; conversely, if downward momentum is stronger, it drops. Why is this indicator useful? Because it intuitively tells you whether the market has overreacted.

When it comes to overbought and oversold signals, this is the most commonly used cue by most traders. When RSI exceeds 70, the market is usually overly optimistic and may face a pullback risk; below 30 indicates excessive pessimism, with a higher chance of a rebound. My personal habit is to pay closer attention when RSI exceeds 75 or drops below 25, because the 70 and 30 boundaries can sometimes produce false signals.

If you want to understand how the RSI formula works in detail, it’s not difficult. RSI equals 100 minus 100 divided by (1 plus RS), where RS is the average gain divided by the average loss. The default calculation uses the past 14 candles, which is a balanced choice to filter noise and improve accuracy. However, this is just the basic version; more complex smoothed RSI formulas weight recent gains and losses, making short-term fluctuations more prominent.

Regarding parameter adjustments, this is where it gets interesting. The standard RSI 14 suits 4-hour and daily charts, but if you're a short-term trader, you might try RSI 6, which reacts much faster but can generate more false signals. Long-term investors are advised to use RSI 24, which produces fewer signals but with higher accuracy. The key is to find parameters that match your trading style—there's no absolute best setting.

Besides overbought and oversold zones, RSI divergence is also a powerful signal. Divergence occurs when the price and RSI indicator move in opposite directions. For example, if the price hits a new high but RSI doesn’t follow suit, that’s called bearish divergence, often indicating waning upward momentum; conversely, bullish divergence suggests weakening downward momentum. I usually rely on TradingView’s automatic divergence detection to avoid missing these signals.

But here’s an important reminder: RSI divergence does not necessarily mean a trend reversal. It only indicates a potential risk of momentum weakening. I’ve seen too many people go short immediately after spotting bearish divergence and get squeezed out, so my approach is to reduce positions when divergence appears to mitigate risk, rather than taking a contrarian trade right away.

Another common mistake is ignoring the differences in timeframes. Some traders see oversold signals on the 15-minute chart and want to enter, but overlook that the daily RSI has already fallen below the 50 midline. As a result, the smaller timeframe’s signal is suppressed by the larger cycle, leading to losses. Now, my habit is to first confirm the trend direction on the higher timeframe before looking for entry points on lower timeframes.

In strong trending markets, RSI can also produce false signals. During a vigorous rally, RSI might stay above 70 or even over 80 for a long time. If you go short just because of overbought signals, you might get pushed higher by the trend. Therefore, RSI overbought and oversold signals are best confirmed with other tools, such as candlestick patterns, trendlines, or MACD.

In summary, RSI is a practical tool that’s easy to learn, but don’t rely on it excessively. My trading approach is to use the RSI formula and divergence to gauge market momentum, combined with moving averages and candlestick patterns to confirm entry points. This combination tends to improve your win rate significantly. For beginners, I recommend starting with the default RSI 14 to get familiar with it, then adjusting parameters once you find your rhythm. The most important thing is to develop a complete trading system, rather than relying solely on a single indicator to make money.