The Fear and Greed Index
A 0-100 gauge of crowd mood, assembled from volatility, momentum, volume and social signals. A thermometer, not a forecast.
Updated September 4, 2026
What the number is made of
The index combines several measurements of the same thing — how the crowd feels. Volatility relative to recent norms, momentum and volume against their averages, social media activity, and search interest.
Sonarcast reads it from alternative.me rather than computing its own. It is a market-wide number: one value for crypto as a whole, not per coin.
Only the extremes say anything
A reading of 50 tells you nothing — the crowd is neither fearful nor greedy, which is the normal state. The value of the index lives entirely in its tails.
Below roughly 20 (extreme fear) and above roughly 80 (extreme greed) it becomes worth reading, because those states are where positioning gets one-sided and therefore fragile.
Why it reads contrarian
Extreme greed means most people who wanted to buy already have. There is little fuel left, and a lot of positions that will be sold if price turns.
Extreme fear is the mirror: those who wanted out are out, and the selling that pushed price down has spent itself. This is the same mechanic as funding extremes — a crowded side is a fragile side, not a wrong one.
What it cannot do
It has no timing. Extreme greed can persist for weeks while price keeps rising, and extreme fear can deepen. "The index is at 85" is not a reason to short; it is a reason to treat new longs more carefully.
It is also market-wide, so it says nothing about any individual coin. A coin can be in its own panic while the index reads greed, and the index will not know.
Common questions
- Should I buy at extreme fear?
- The index says positioning is one-sided, not that the bottom is in. Extreme fear can persist and deepen for weeks. It is context for a decision, not the decision.
- What counts as an extreme?
- Roughly below 20 and above 80. Between those, the reading is noise — the crowd being mildly optimistic is not information.
- Does the index apply to individual coins?
- No. It is one number for the whole crypto market. A coin can be crashing while the index reads greed; for a single coin use its own funding, open interest and structure.