Methodology
Altcoin Season Index Methodology
How the Altcoin Season Tracker selects assets, compares performance against Bitcoin, calculates index values, and handles historical data.
The index measures market breadth: how many leading, investable altcoins are beating Bitcoin over the same period.
Index universe
We start with the largest cryptocurrencies by market capitalization and select the first 50 eligible altcoins. Bitcoin is the benchmark, not a constituent.
Exclusions
Stablecoins, fiat-pegged assets, wrapped assets, liquid-staking receipts, and commodity-backed tokens are excluded because their intended price behavior makes comparison misleading.
Calculation
For each period, an altcoin receives one point when its percentage return is greater than Bitcoin's return. The score is the percentage of eligible coins that receive a point, rounded to the nearest whole number.
Interpretation
- 0–25: Bitcoin Season
- 26–74: Neutral or transitional market
- 75–100: Altcoin Season zone
Threshold reading versus confirmed altcoin season
The zones above describe the index alone. A reading of 75 or more is a threshold reading: breadth has reached the altcoin season zone. This site calls an altcoin season confirmed only when the index is 75 or more and Bitcoin dominance is 42% or less on the same day, because broad outperformance while Bitcoin still holds most of the market's value has often been short-lived. A single day at 75 with dominance above 42% is reported as a threshold reading, not as an altcoin season.
Worked example
Say Bitcoin rose 12% over the last 90 days. Of the 50 eligible altcoins, 39 rose by more than 12% and 11 rose less or fell. The index is 39 ÷ 50 × 100 = 78. That is a threshold reading; it becomes a confirmed altcoin season only if Bitcoin dominance is 42% or less on the same day.
Data source and timing
Prices, market capitalization, volume and category data come from CoinGecko. Current data refreshes about every four hours, and one snapshot per day is kept as the durable record. Every dated figure on this site is the value in that day's stored snapshot.
Why this index differs from other providers
Several sites publish an "Altcoin Season Index", and on the same day they can show different numbers. None of them is wrong: they answer slightly different questions. The readings differ for four reasons.
- Universe size. This index uses the 50 largest eligible altcoins. Others use the top 100, which adds smaller and more volatile coins.
- Exclusions. Providers remove different assets. This index excludes stablecoins, fiat-pegged assets, wrapped assets, liquid-staking receipts and commodity-backed tokens.
- Window. The headline here is 90 days. A 30-day or 7-day reading from another provider can sit far from it.
- Snapshot time and membership. Each stored day keeps the membership it had on that day, so history is not rewritten when the top 50 changes.
When comparing providers, compare the universe and the window first. The daily record behind this index can be downloaded as CSV.
90-day data
The primary 90-day score uses each constituent's Bitcoin-denominated price history. When a fresh deployment is still collecting that history, the interface explicitly labels the shorter-window score as provisional rather than presenting an estimate as exact.
Historical charts
Daily snapshots are stored locally. This means the history is reproducible and expands every day instead of changing when the current top-50 membership changes.
Limitations
Market-cap rankings change, crypto data providers can experience gaps, and outperformance alone does not measure liquidity, risk, or project quality. The index is market context, not a recommendation to trade.