Shown with every coin it is built from
The index counts how many of the top coins have outperformed Bitcoin over a chosen window and expresses it as a percentage. The widely used convention takes the top 50 by market capitalisation, excludes stablecoins and wrapped assets, looks back 90 days, and calls a reading of 75 or above an altcoin season and 25 or below a Bitcoin season. This page follows that definition and computes it in your browser from Binance daily closes.
The difference here is that the constituent list is on the page. A single number cannot be checked — you cannot tell which coins were counted, whether one of them is a stablecoin that should have been excluded, or whether the reading rests on a handful of outliers. Showing every coin and its return next to Bitcoin's makes the index verifiable rather than something to take on faith.
Two properties are worth keeping in mind while reading it. It is purely relative, so during a broad decline in which altcoins fall less than Bitcoin the index can read as an altcoin season while everything on the list is down — the returns column makes that visible. And the 75 and 25 lines are conventions rather than measured regime boundaries, so a reading a point or two either side of them is better read as borderline than as a change of state.
⚠️ Not investment advice. This index describes past relative performance and carries no forecast. The universe is ranked by trading volume rather than market cap, so membership can differ from other trackers. All decisions and risks are your own.
It is the share of the top coins that have outperformed Bitcoin over a chosen window, expressed as a percentage. The common convention looks back 90 days across the top 50 coins excluding stablecoins and wrapped assets, and calls 75 or above an altcoin season and 25 or below a Bitcoin season.
They are conventions rather than measured regime boundaries. Nothing changes in the market between a reading of 74 and 76, so a value near either line is better read as borderline than as a change of state. This page flags readings within five points of a threshold for that reason.
Yes, and this is the most common misreading. The measure is purely relative, so in a broad sell-off where altcoins fall less than Bitcoin the index rises even though every coin is losing money. The page shows each coin’s own return alongside its performance against Bitcoin so that case is visible.
The universe here is ranked by trading volume rather than market capitalisation, because a static site has no market-cap feed and volume is the closest public proxy Binance offers. The two usually agree on membership but not always. Since the full list is shown, any difference is easy to inspect rather than hidden.
Bitcoin itself, stablecoins such as USDT, USDC, FDUSD and DAI, and Bitcoin or Ethereum wrappers such as WBTC and WBETH. Including them would drag the index toward the middle, since a stablecoin neither beats nor loses to Bitcoin in any meaningful sense.
No. The index is entirely backward looking — it reports that altcoins have already outperformed over the window you selected. It contains no forecast, and this page does not turn it into one.