RSI is the first indicator most people learn and the first one they misuse. The usual lesson — "above 70 means sell, below 30 means buy" — is not just oversimplified. In the exact conditions where it feels most convincing, it's often backwards.
Let's fix that. RSI is worth knowing well; it just isn't the traffic light it's sold as.
What RSI actually measures
The Relative Strength Index is a momentum gauge. Over a look-back window — 14 days by default — it compares the size of recent up-moves to recent down-moves and boils that into a single number from 0 to 100. High means gains have been dominating; low means losses have. That's it. It's a measure of how one-sided recent price action has been, nothing more.
Crucially, RSI says nothing about value, fundamentals, or where a price "should" be. It only describes the character of the recent move.
The 30/70 rule everyone repeats
The convention is that RSI above 70 is "overbought" and below 30 is "oversold," with the unspoken implication that overbought means sell and oversold means buy. As a vocabulary for describing momentum, the 70/30 markers are fine. As a trading rule, they quietly assume the thing you most need to check first.
"Overbought" is a description of momentum, not a prediction of reversal. Strong things stay overbought.
Why it's a trap in a trend
Here's the failure mode. In a strong uptrend, RSI can push above 70 and stay there for weeks while the price keeps climbing. Someone selling every time RSI crossed 70 in a powerful advance would have sold the best-performing names again and again, far too early. The same works in reverse: in a real downtrend, RSI can sit below 30 for a long time, and each "oversold" reading that looks like a bargain is just the trend continuing.
So the level alone tells you almost nothing. What gives it meaning is context: the trend it's sitting inside, and whether momentum is confirming or diverging from price.
What experienced readers look at instead
The trend first. In a clear uptrend, RSI hovering in the 40–80 range is normal strength, not a warning. In a downtrend, 20–60 is the normal range. Read the level relative to the trend, not against a fixed 30/70.
Divergence. The more informative signal is when price makes a new high but RSI makes a lower high — momentum fading even as price rises. That disagreement is worth noticing far more than any single threshold crossing.
The stock's own history. Some names routinely run hot; others rarely leave the middle. RSI is most useful compared to how that particular ticker has behaved, not a universal line.
At 58.2, momentum leans mildly positive but sits well inside the neutral zone — neither stretched nor washed out. There's no overbought signal here, and with price near recent highs it's worth watching whether RSI keeps pace or starts to lag on the next push.
Educational commentary — not adviceThat's the whole point of the tool: the 58.2 is computed exactly, in code, and the plain-language read interprets it in context instead of just reciting "neutral." The number is never guessed. (Example reading — a point-in-time snapshot, not current data.)
Takeaways
- RSI measures momentum, not value — how one-sided recent moves have been, on a 0–100 scale.
- 70/30 are descriptions, not signals. In a strong trend, RSI can stay "overbought" or "oversold" for a long time.
- Read it against the trend and watch for divergence — that's where the information is.
- Compare to the ticker's own history, not a universal line.
See RSI on a stock you care about
Pull up any ticker, get the exact RSI computed alongside the trend, and a plain-language read of what it means in context.
Launch app →Roos Research provides educational information and commentary only and does not offer financial, investment, or trading advice. Markets carry risk; do your own research.