What the RSI is and how to read it in crypto

The RSI is the most widely used momentum oscillator in technical analysis. Read well, it measures the exhaustion of a move; read poorly, it is the single most common cause of premature counter-trend entries.

Definition and formula

The Relative Strength Index, created by J. Welles Wilder in 1978, is an oscillator bounded between 0 and 100 that compares the magnitude of recent gains against recent losses. Its standard period is 14 candles.

Wilder uses his own exponential smoothing (the so-called Wilder smoothing): each new value weighs the accumulated history, so the RSI "remembers" more than a simple average would. The detail matters: two platforms computing the smoothing differently will show different values for the same candle.

The classic levels: 70 and 30

By convention, an RSI above 70 signals statistical overbought conditions and an RSI below 30, oversold. The 45–55 area is considered neutral or trending.

The nuance that separates the analyst from the beginner: overbought does not mean sell. In a strong uptrend —routine in crypto— the RSI can hold above 70 for weeks while price keeps climbing. In trending markets it is more useful to read the ranges the RSI respects: in an uptrend, pullbacks tend to stall in the 40–50 area instead of reaching 30; in a downtrend, bounces die at 50–60 without touching 70.

The RSI changes with the timeframe

An RSI of 75 on 1-hour candles is everyday noise; an RSI of 75 on weekly candles describes the state of an entire cycle. Serious analysis contrasts several timeframes at once, subordinating the short-term reading to the larger structure. On Bitcoin, a weekly RSI above 85 has historically coincided with end-of-cycle euphoria, while monthly readings under 40 have only appeared at the bottoms of deep bear markets.

Divergences: the highest-quality signal

A divergence appears when price and indicator contradict each other, and it is one of the most reliable exhaustion signals in technical analysis:

Bearish divergence: price prints a higher high while the RSI prints a lower high. The rally is losing internal strength —a potential top. Bullish divergence: price prints a lower low while the RSI draws a higher low: selling pressure is drying up.

The practical challenge is separating real divergences from noise. Two filters help: require that the compared highs/lows are valid pivots (standing out against several candles on each side, not any minor wiggle), and check that capital flow does not contradict the signal —a bullish divergence with no buying volume behind it is usually a trap.

StochRSI: the hypersensitive cousin

The StochRSI applies the stochastic formula to the RSI itself (common parameters 3,3,14). The result is an ultra-fast oscillator that flags microscopic turns: useful for fine-tuning entry timing within an already confirmed trend, but far too noisy as a standalone signal.

Common mistakes

Selling just because the RSI touches 70 in a strong uptrend. Trading divergences on minute charts, where noise dominates. Ignoring that the daily and weekly RSI can say opposite things —and the higher one rules. And comparing RSI values across platforms without checking they use the same smoothing.

Frequently asked questions