RSI & momentum

RSI compares the size of recent gains to the size of recent losses over a lookback period (14 bars by default) and packs the result into a 0–100 reading. A high RSI means gains have dominated and momentum is strongly up; a low RSI means losses have dominated. It's a normalised, comparable read on momentum across any market or timeframe.

The standard reference lines are 70 and 30. Above 70 is labelled 'overbought,' below 30 'oversold,' with 50 acting as a rough midline between bullish and bearish momentum. But — and this is the crucial part — those labels are alerts, not commands.

The single biggest RSI mistake is shorting just because RSI is over 70, or buying just because it's under 30. In a powerful trend, RSI can sit pinned in overbought for a very long time while price keeps climbing. Fading strength blindly is how traders bleed out against a freight train.

Treat overbought/oversold as a heads-up that a move is extended and may be due a pause or pullback — then demand a second reason (a level, a pattern, a structure break) before acting. In strong trends, the more useful trick is to use the 40–50 zone: in an uptrend RSI often bottoms around 40 on pullbacks rather than reaching 30, giving earlier entries.

The most powerful RSI signal isn't the levels at all — it's divergence. Bearish divergence occurs when price makes a higher high but RSI makes a lower high: price is grinding to new peaks, but the momentum behind each push is fading. It's an early, leading warning that the trend is running out of fuel.

Bullish divergence is the mirror and often marks bottoms: price makes a lower low while RSI makes a higher low, hinting that selling pressure is exhausting even as price dribbles lower. Divergence doesn't time the exact turn, but it tells you to tighten stops, take profit, or get ready for a reversal setup.

RSI shines as a confirmation and timing layer, not a standalone system. Combine it with structure: a bullish divergence forming right at a support zone, in line with the higher-timeframe trend, is a genuinely high-quality long. The oscillator tells you momentum is turning; the level tells you where.

Adjust the lookback to your style — shorter periods (e.g. 7) are jumpier and suit fast trading; longer periods (e.g. 21) are smoother for swing trading. And resist stacking five momentum tools: RSI and MACD measure similar things, so use them to confirm each other, not to clutter the chart.