BTC dominance (BTC.D) measures Bitcoin's share of total crypto market cap. It's the key indicator for altcoin season timing.
If BTC.D drops, how much does your alt gain vs just holding BTC?
| Date | Event | BTC.D | What Happened |
|---|---|---|---|
| Jan 2017 | Pre-ICO boom | 87% | BTC dominated; alts barely existed |
| Jan 2018 | ICO alt season peak | 33% | Massive alt season — ETH, XRP 10× in weeks |
| Jan 2020 | Pre-DeFi | 68% | BTC dominance high; DeFi summer coming |
| May 2021 | Alt season peak | 40% | DOGE, SHIB, BNB massive moves |
| Jan 2023 | Bear bottom | 42% | BTC outperformed; alts still down |
| Dec 2024 | BTC new ATH cycle | 60% | BTC led; alts lagging |
| Q2 2025 | Alt rotation begins | 55% | ETH/SOL start catching up |
| BTC.D Level | Signal | Strategy |
|---|---|---|
| >65% | Strong BTC dominance | Stick to BTC. Alts underperform. |
| 55–65% | BTC still ahead | Hold BTC, watch ETH for rotation signals. |
| 45–55% | Transition / early alt season | Slowly rotate into large-cap alts. |
| 35–45% | Alt season active | Alts outperforming. High risk/reward. |
| <35% | Full alt season / top risk | Historically near cycle top. Consider exits. |
What is Bitcoin dominance (BTC.D)? Bitcoin dominance is Bitcoin's market cap as a percentage of the total crypto market cap. It rises when BTC outperforms altcoins and falls when altcoins outperform BTC, making it the standard gauge for whether capital is flowing into Bitcoin or rotating into the wider altcoin market.
What BTC.D level signals altcoin season? As a rough guide, BTC.D above 65% means BTC dominance is strong and alts underperform; 45-55% is a transition zone where large-cap alts start rotating in; below 45% (and especially under 35%) has historically marked active altcoin season, with the deepest alt seasons (Jan 2018 at 33%, May 2021 at 40%) coinciding with dominance lows that were followed by major corrections.
Does falling BTC.D always mean altcoins are going up in price? Not necessarily. BTC.D is a ratio, so it can fall either because altcoins are rising faster than Bitcoin or because Bitcoin's price is falling while altcoins fall less. Always check BTC.D alongside absolute price action — a dropping dominance percentage during a broad market decline is a different signal than one during a rally.