In this lesson
- find out how closely ETH moves with Bitcoin
- understand what beta is and why ETH swings more
- learn to read the ETH/BTC ratio
ETH and BTC are like two people on a seesaw holding hands: most of the time they go up and down together. One of them just swings harder. And now and then it turns out one is sitting on the longer end.
How closely they move#
From weekly data, January 2021 to September 2026:
- The correlation of ETH's and BTC's weekly changes is 0.79. When Bitcoin rises or falls, ETH mostly does too.
- ETH swings roughly 1.35× more than Bitcoin.
- ETH's beta to Bitcoin is around 1.07: when Bitcoin makes +10% in a week, ETH on average makes a bit over +10% – but with a wide spread around that average.
For you it means: ETH next to Bitcoin does not spread risk much. In a big market fall it usually falls with Bitcoin, and often more.
The ETH/BTC ratio#
The ETH/BTC ratio says how much bitcoin one ETH costs. When it rises, ETH is leading; when it falls, Bitcoin is – even if both rise in dollars.
- ETH/BTC
In December 2021 one ETH cost 0.0884 BTC. In April 2025 only 0.01766 BTC – 80% less. So whoever swapped bitcoin for ETH at the end of 2021 because "ETH has better technology" had only a fifth of their original bitcoins three years later. In August 2025 the ratio climbed back above 0.043; at the end of September 2026 it was 0.032.
Why the ratio changes so much#
The fall in 2022–2025 is usually explained by several things at once: big investors' interest in Bitcoin (bitcoin ETFs came earlier and drew more money), the growth of rival networks such as Solana, and activity moving to layer 2 networks, which burn almost nothing on Ethereum. None of them is enough on its own – and nobody knew in advance how it would turn out.
An altcoin is not diversification
ETH next to Bitcoin in a portfolio does not spread the risk – it adds a bet on a market moving in the same direction, only harder. Real diversification means assets that do not depend on crypto.
Common myths#
- "ETH moves independently of Bitcoin." A correlation of 0.79 says the opposite.
- "When ETH rises in dollars, it is leading." It can be losing against Bitcoin at the same time.
- "Better technology = a better result against BTC." Between 2022 and 2025 ETH lost 80% against BTC.
Summary
- The weekly correlation of ETH and BTC is 0.79; ETH swings about 1.35× more.
- The ETH/BTC ratio shows which of the two is leading.
- The ratio fell from 0.0884 (December 2021) to 0.01766 (April 2025), i.e. by 80%.
- ETH next to Bitcoin does not spread risk.