RSI: Reading Momentum, Not Predicting Tops

The Relative Strength Index (RSI) is one of the most popular momentum indicators — and one of the most misread. It does not tell you a top is in. It tells you how fast and how far price has moved recently, on a scale from 0 to 100.

What RSI measures

RSI compares the size of recent up moves to recent down moves over a lookback period — usually 14 candles. When gains dominate, RSI rises toward 100. When losses dominate, it falls toward 0. A reading near 50 means up and down pressure are roughly balanced.

You do not need to compute it by hand. What matters is understanding what the line is reacting to: the speed of the move, not its direction alone.

Overbought and oversold — the common trap

The textbook says RSI above 70 is “overbought” and below 30 is “oversold.” Beginners read that as “above 70 means sell.” That is where accounts get hurt.

In a strong trend, RSI can sit above 70 for a long time while price keeps climbing. Overbought does not mean “about to fall” — it means “moving fast.” In a range, those levels are more useful; in a trend, they are often just describing strength.

Divergence — the signal worth learning

The more reliable use of RSI is divergence: when price and RSI disagree.

• Bearish divergence — price makes a higher high, but RSI makes a lower high. Momentum is fading even though price ticked up.
• Bullish divergence — price makes a lower low, but RSI makes a higher low. Selling pressure is weakening.

Divergence is not a trigger by itself — it is a warning that the current move is running out of fuel. It still needs confirmation from price.

The limitation

RSI is derived from past price, so it lags. It produces false signals in choppy markets and can stay “extreme” far longer than feels reasonable. It is a lens on momentum, not a timing machine.

A realistic expectation

Treat RSI as context — “is this move accelerating or tiring?” — not as a buy/sell button. It works best alongside price structure and support/resistance, never alone. Nothing here is financial advice.

Practice it

Spotting divergence is a skill you build by reps, not by reading. Try the RSI Divergence Practice drill and train your eye to see when price and momentum pull apart.