RSI (14d)

The Relative Strength Index (J. Welles Wilder, 1978) measures the speed of recent price changes: it compares the average size of up-days against down-days over the last 14 days and maps the result to a 0–100 scale. Persistent buying pushes it toward 100, persistent selling toward 0.

The standard reading: above 70 is "overbought" (the rally is stretched and prone to a pause), below 30 is "oversold" (selling is exhausted). In strong crypto bull markets the daily RSI can pin above 70 for weeks, so overbought is not an automatic sell — the more reliable signals are oversold readings during established uptrends, and divergences, where price makes a new high but RSI makes a lower high, hinting momentum is fading.

RSI is a fast momentum gauge, best for timing within a trend. It says nothing about valuation — pair it with the slower metrics (risk, Mayer) for the bigger picture.