Altcoin
An altcoin is any cryptocurrency other than bitcoin; the name comes from "alternative coin". Many altcoins have higher volatility and lower liquidity than BTC.
How it works
The first altcoins were copies of bitcoin with changed rules. Today there are thousands: coins of smart-contract blockchains (ETH, for example), DeFi service tokens, gaming tokens and meme tokens. Stablecoins are technically altcoins too, but are often treated as a separate group.
Altcoins usually follow bitcoin: when BTC falls, most alts fall harder. Small coins have few buyers and sellers, so a large order moves the price and getting out in a panic can be hard.
Before buying, people look at market cap, tokenomics (how many coins exist, who holds them and when they unlock), real usage and trading volume. This is no promise of growth, just a way to filter out clearly weak projects.
Bitcoin drops 10%. An altcoin with a $50 million market cap drops 25% over the same time: on $1,000 invested that is minus $250 versus minus $100 in BTC.
You want to sell $5,000 of an alt, but the order book near the price only holds $1,500 of bids. To sell everything you have to go deeper, and your average price ends up noticeably worse (that is slippage).
The most common mistake is buying an alt because it is "cheap" per coin or everyone is talking about it. The price of one coin means nothing without market cap and supply. Do not put more into small altcoins than you can afford to lose, and check the unlock schedule: large token releases often push the price down.
Questions and answers
What is an altcoin in simple terms?
It is any cryptocurrency that is not bitcoin. For example ETH, SOL or any meme token.
Is Ethereum an altcoin?
Yes, technically Ethereum is an altcoin because it is not bitcoin. But it is the largest one with its own ecosystem, so it is often discussed separately.
What is altcoin season?
It is a period when altcoins on average rise faster than bitcoin. It does not happen every cycle and does not follow a schedule.
Related terms
Read next
Step by step, from picking an exchange to coins sitting in your own wallet. No leverage, no shortcuts, and a check at every step.
Read →AltseasonAltseason is a period when most altcoins rise noticeably faster than bitcoin. It usually comes with falling BTC…
Updated: 2026-10-19