What is altcoin season?
Altcoin season (altseason) is a stretch of the market when most altcoins outperform Bitcoin. Money rotates out of BTC into other coins and their prices rise faster, or fall slower. The opposite, when Bitcoin beats most altcoins, is Bitcoin season. The altcoin season index turns that idea into one number from 0 to 100 (see also the glossary entry).
Our exact calculation
- Pick the coins. Rank every coin by its 24-hour perpetual futures volume across the exchanges we track and take the top 50 that have a Binance spot USDT market, skipping the exclusions below. We use no market-cap feed, so perp volume stands in for size.
- Measure returns. For each coin take the last completed UTC daily close on Binance spot and the close 90 days earlier. The return is close ÷ earlier close − 1. Do the same for BTC on BTCUSDT.
- Count the winners. A coin beats Bitcoin when its 90-day return is strictly greater than Bitcoin's. A coin that fell 5% while BTC fell 10% counts as a win.
- Divide. Index = coins that beat BTC ÷ coins with both closes × 100. With fewer than 10 coins counted there is no reading.
The history chart repeats the same calculation for each past day, using today's coin list; it shows the last 365 days.
Worked example (made-up numbers)
Bitcoin went from $60,000 to $66,000 over the 90 days, a return of +10%. 13 altcoins made the list (“then” is the close 90 days ago, “now” yesterday's close):
| Coin | Then | Now | Return | Beat? |
|---|---|---|---|---|
| AAA | 1.00 | 1.45 | +45% | yes |
| BBB | 2.00 | 2.60 | +30% | yes |
| CCC | 10.00 | 12.00 | +20% | yes |
| DDD | 0.50 | 0.58 | +16% | yes |
| EEE | 4.00 | 4.48 | +12% | yes |
| FFF | 1.00 | 1.11 | +11% | yes |
| GGG | 20.00 | 22.40 | +12% | yes |
| HHH | 3.00 | 3.42 | +14% | yes |
| III | 8.00 | 8.96 | +12% | yes |
| JJJ | 1.00 | 1.05 | +5% | no |
| KKK | 5.00 | 5.00 | +0% | no |
| LLL | 2.00 | 1.60 | −20% | no |
| MMM | — | 0.90 | — | skip |
MMM was not listed 90 days ago, so it is skipped and 12 are counted. 9 of them beat Bitcoin: index = 9 ÷ 12 × 100 = 75, which reads as Altcoin season.
What is excluded
- Bitcoin itself, the benchmark.
- Stablecoins (55 tickers: AEUR, BFUSD, BIDR, BKRW, BUSD, BVND, CRVUSD, CUSD, DAI, DOLA, EUR, EURC, EURI, EURS, EURT, FDUSD, FDUSDC, FRAX, GHO, GUSD, GYEN, HUSD, IDRT, LISUSD, LUSD, MIM, PYUSD, RLUSD, SUSD, SUSDE, SUSDS, TRYB, TUSD, U, USD0, USD1, USDB, USDC, USDD, USDE, USDF, USDG, USDJ, USDL, USDN, USDP, USDQ, USDS, USDT, USDTB, USDX, UST, USTC, XUSD, ZUSD). Their price follows a currency, not the market.
- Wrapped, staked and pegged tokens (40 tickers: BBSOL, BETH, BNSOL, BTCB, BTCDOM, CBBTC, CBETH, DEFI, EETH, HBTC, JITOSOL, KAG, KAU, LBTC, METH, MSOL, PAXG, RENBTC, RETH, SOLVBTC, STETH, STHYPE, STSOL, TBTC, UBTC, UETH, WAVAX, WBETH, WBNB, WBTC, WEETH, WETH, WHYPE, WMATIC, WPOL, WSOL, WSTETH, WTRX, XAUM, XAUT). Their price follows another asset, such as BTC, ETH or gold.
- Coins without a Binance spot USDT market, since the returns come from Binance spot candles, and HIP-3 stock and commodity perps on Hyperliquid.
- Coins listed less than 90 days ago or without yesterday's close. The index page lists these coins and how much history each has.
Thresholds and labels
| Index | Label |
|---|---|
| 75 or above | Altcoin season |
| Between | Neutral |
| 25 or below | Bitcoin season |
| No reading | No data |
At 75 or above at least three in four altcoins beat Bitcoin; at 25 or below Bitcoin beat at least three in four. “Between” means above 25 and below 75: neither side leads. There is no reading with fewer than 10 coins that have 90 days of history, or when the candles could not be loaded.
Why 90 days?
A 90-day window is long enough that one strong week, a single listing pump or a short squeeze cannot flip the reading, and short enough to catch a rotation within a quarter. It is also the window the widely cited altcoin season indexes use. The trade-off is lag: the index confirms a rotation weeks after it starts, and it can stay high after the rally has ended because the start of the window still sits before the move.
How it differs from Bitcoin dominance
Bitcoin dominance is Bitcoin's share of the total crypto market cap, a size measure from CoinGecko. The altcoin season index is a breadth measure: it counts how many altcoins beat Bitcoin's return, and every coin counts the same, whatever its size. Falling dominance often comes with a rising index, but not always. A rally in ETH alone lowers dominance while most smaller coins still lag BTC, and a stablecoin inflow lowers dominance without any altcoin rising.
Limits
- The coin list is ranked by perpetual futures volume, not market cap, so it leans towards actively traded coins.
- Past values use today's list. Coins that have since dropped out are missing (survivorship bias), which can flatter past altcoin performance.
- Returns are Binance spot USDT closes at the UTC day boundary; other venues and quotes can differ slightly.
- The index counts winners, not by how much they won. One coin up 200% and one up 1% over BTC count the same.
- It describes the last 90 days. It is not a forecast and not financial advice.
Data sources checked on 19 October 2026: Binance spot API: kline/candlestick data · CoinGecko API: global market data. Not financial advice.