DEFINITION
A 0–100 gauge of crypto market sentiment that blends volatility, momentum, volume, social chatter, and bitcoin's market-cap dominance into one number. 0–24 reads "extreme fear," 75–100 "extreme greed."
The best-known version is published daily by alternative.me. It exists because markets overreact: when prices fall, fear compounds selling; when they rise, greed chases the top. The index compresses that mood into a single dial so you can see — at a glance — whether the crowd is panicking or euphoric. Contrarians read it backwards, following Warren Buffett's line about being "fearful when others are greedy, and greedy when others are fearful."
It is a sentiment thermometer, not a price oracle. Extreme fear can persist for months — as it did through the summer of 2026, with the index pinned near the floor while bitcoin chopped inside its
$59K–$71K range — and extreme greed can run far longer than a short-seller's margin. Most long-term holders use it as context for a
dollar-cost averaging plan rather than a trading signal.
Key facts
Scale0 (extreme fear) – 100 (extreme greed)
InputsVolatility, momentum, social, dominance
UpdatedDaily (alternative.me)