RSI, Explained: How the Relative Strength Index Spots Overbought and Oversold Assets

What the Relative Strength Index Is and Why Traders Watch It

The Relative Strength Index (RSI) is one of the most widely used technical indicators in financial markets, and it is the subject of a recent primer published by the business site Be. In essence, RSI is a momentum gauge: it compares the size of recent gains with recent losses over a fixed period — typically 14 trading days, as the source notes — and turns that relationship into a single reading for an asset.

The indicator is designed to answer a straightforward question: is an asset overbought, meaning the buying push has stretched unusually far, or oversold, meaning selling has been excessive? When the RSI enters those extreme zones, technically oriented traders often look for a pause or reversal in the price move, using the reading to help time entries and exits.

The source article contains no specific market event, asset, company or price move. It is an educational explainer rather than a news report, so its practical value lies in understanding what the indicator measures — and, just as importantly, what it does not measure — before acting on its signals.

How RSI Works, Where It Misleads, and Who Actually Uses It

What the RSI Reading Actually Captures

RSI is built on a ratio of average gains to average losses over a lookback window, most often 14 periods. The result is an oscillator that conventionally runs from 0 to 100: readings above 70 are usually treated as overbought, readings below 30 as oversold. The logic is mean-reversion — after an unusually strong run, the balance of up-days to down-days becomes extreme, and traders expect the pace to normalize.

The source's description stops at the definition, and that is where many users go wrong. An overbought reading is not a sell signal in itself: in a strong trend an asset can stay overbought for weeks while the move continues. RSI describes recent price momentum; it does not forecast the next turn.

Where RSI Misleads

Two errors are common: treating the 70 and 30 extremes as automatic triggers rather than caution flags, and ignoring the lookback period. A 14-day RSI reflects roughly two weeks of price action, so it suits swing-trading timeframes — shorter windows produce more false signals, longer windows react more slowly.

Because RSI is derived from past prices, it is a lagging tool and carries no information about earnings, valuations, news flow or liquidity. Practitioners typically pair it with trend direction, volume and broader market context rather than relying on it alone.

Who Actually Uses It

RSI is mainly a tool for short-term and swing traders timing entries and exits around momentum extremes. For long-horizon, fundamentals-driven investors it says little about an asset's value — a useful reminder given how often technical vocabulary creeps into everyday market commentary.

Using RSI Without Misreading Its Signals

• Treat an RSI reading above 70 or below 30 as a caution flag, not an automatic order to buy or sell — wait for confirmation such as a move back across the threshold or a divergence between price and RSI.
• Match the lookback period to your holding horizon: the source's default of 14 days reflects roughly two weeks of trading, which suits swing trading better than intraday timing or long-term investing.
• Remember that RSI captures only past price momentum. It says nothing about an asset's fundamentals or the news driving the market, so use it alongside trend and volume signals.