Not financial, legal, or tax advice. This guide is for general education only. ETH is volatile and you could lose money. Do your own research and consider consulting a qualified professional before investing.

Ethereum is a decentralized network that lets people run software and agreements directly on a blockchain, without any company hosting them. Its native currency, ether (ETH), pays for that activity, which is why Ethereum is often described as a world computer rather than simply a form of digital money.

Table of Contents

What Ethereum is

Ethereum launched in 2015, proposed by Vitalik Buterin and a group of co-founders who wanted a blockchain that could do more than record payments. Where Bitcoin was designed mainly to move value (see What Is Bitcoin), Ethereum was designed to run arbitrary programs. That single design choice opened the door to a huge range of applications: lending platforms, marketplaces, games, and digital collectibles, all running on shared infrastructure that nobody owns.

If you already understand What Is Blockchain, the simplest way to think about Ethereum is a blockchain with a built-in programming layer. It keeps the ledger of who owns what, and it also executes code that anyone can deploy and anyone can use.

ETH vs. the Ethereum network

People often blur two different things, so it helps to separate them.

Ethereum is the network: the collection of computers running the software, the shared ledger, and the programs deployed on it.

Ether (ETH) is the network's native cryptocurrency. You use it to pay for transactions and computation, and many people also hold it as an investment. When someone says they own Ethereum, they usually mean they own ETH.

This relationship echoes the broader coins-and-tokens picture covered in What Is Cryptocurrency. ETH is the coin that powers the platform; thousands of other tokens are built on top of that platform, as we explain in What Are Crypto Tokens.

What smart contracts are

A smart contract is a program stored on the blockchain that runs automatically when its conditions are met. Think of it as a vending machine for agreements: put in the right input, and the defined output happens, with no clerk in the middle and no ability for either side to renege.

For example, a lending contract can hold collateral, release a loan, and return the collateral when the loan is repaid, all in code, all visible on the public ledger. Because the logic runs exactly as written and cannot be quietly altered, users can interact with strangers and still trust the outcome.

Smart contracts are the foundation of decentralized finance, which we cover in What Is DeFi, and of most token projects (see What Are Smart Contracts for a deeper dive). They are powerful, and they carry a specific risk: if the code contains a bug, that bug executes faithfully too, which has led to real losses.

Gas and transaction fees

Running code on a shared network is not free. Every action on Ethereum, from sending ETH to using a complex application, costs a fee measured in units called gas. Gas exists for two reasons: it compensates the validators who process transactions, and it prevents anyone from clogging the network with endless computation.

The total fee depends on how much computation your action requires and how busy the network is at that moment. When many people transact at once, fees rise; when activity is quiet, fees fall. High gas fees during busy periods have been one of Ethereum's longest-standing pain points, which is a big part of why scaling solutions matter.

Layer 2s and scaling

Because the main Ethereum network (often called layer 1\) can only process so many transactions at once, developers built layer 2 networks that sit on top of it. These handle transactions off the main chain in bulk, then post a compressed summary back to Ethereum for security. The result is much faster and cheaper transactions while still relying on Ethereum's underlying trust.

Ethereum also changed how it secures the network. In an upgrade known as the Merge, it moved from proof of work to proof of stake, where validators lock up ETH as collateral instead of running energy-hungry mining hardware. This cut the network's energy use dramatically and introduced staking, a way for holders to help secure the network and earn rewards (see What Is Staking).

Risks to understand

  • Price volatility. ETH can move sharply in either direction. Only invest what you can afford to lose.
  • Smart contract risk. Bugs or exploits in applications built on Ethereum can drain funds, even when Ethereum itself works as intended.
  • Fees. During busy periods, transaction costs can be high, which matters for small transactions.
  • Complexity. The ecosystem is large and fast-moving, which makes it easy for newcomers to stumble into risky or fraudulent projects. See How to Keep Your Crypto Safe.
  • Regulatory and tax uncertainty. Treatment of ETH and staking rewards varies by country and can change.

How to get started

A sensible path is to understand the foundations first (What Is Blockchain, What Is Cryptocurrency), then decide how you want to hold ETH. You can buy a small fraction through a reputable platform, and you can store it yourself using a wallet (see What Is a Crypto Wallet). If ETH is something you want to accumulate gradually rather than buy all at once, a recurring plan can smooth out the ups and downs, an approach discussed in What Does HODL Mean in Crypto.

Add ETH to a recurring Hodl Up plan. If you would rather build an Ethereum position steadily than try to time a volatile market, Hodl Up lets you buy ETH automatically on a schedule that fits your budget. Set your plan and let it run.