Ethereum explained: what it is, how it works and what to watch out for

Bitcoin was built to do one thing: move value without a bank in the middle. Ethereum took the same basic idea, a shared ledger that no single company controls, and asked a bigger question. What if that ledger could also run programs? This guide covers Ethereum explained in plain terms: what the network is, how ether differs from the network itself, what smart contracts actually do, and where the real risks sit for an ordinary person thinking about using it.

If you are new to the subject, it helps to start with our plain English guide to Bitcoin and how a blockchain works, because Ethereum builds directly on both.

Ethereum explained: the network versus the coin

People use "Ethereum" to mean two different things, and mixing them up causes a lot of confusion.

Ethereum is the network. It is a blockchain run by thousands of independent computers, called nodes, that each keep a copy of the same record and agree on every change to it.

Ether, usually written as ETH, is the native currency of that network. You need ETH to do almost anything on Ethereum, because every action costs a small fee that is paid in ether.

A useful comparison is a city's road system and the fuel that cars burn on it. The roads are Ethereum. The fuel is ETH. You can talk about the price of fuel without saying anything about whether the roads are well designed, and the reverse is also true.

What makes Ethereum different from Bitcoin

Bitcoin's ledger mostly tracks one thing: who owns how much bitcoin. Its scripting system is intentionally limited, which keeps it simple and hard to break.

Ethereum was designed as a general purpose computer that lives on a blockchain. Developers can write programs, upload them to the network, and those programs then run exactly as written on every node. Once deployed, they are very hard to change or stop, which is both the point and the danger.

That flexibility is why Ethereum hosts so much of the activity people associate with crypto beyond simple payments: tokens, digital collectibles, lending apps, exchanges that run without a company behind them, and many of the dollar backed tokens known as stablecoins.

What a smart contract actually is

The term "smart contract" oversells it a little. A smart contract is not a legal document and it is not intelligent. It is a program stored on the blockchain that follows simple if this, then that rules.

Here is a concrete example. Imagine a contract that holds funds for a group trip. The rule says: if four of the six friends approve a payment, send the money to the address they named. Nobody has to trust a single organizer with the pot. The code enforces the rule, and every step is visible on the public ledger.

Real contracts handle much more:

• Tokens. Many coins you see listed on exchanges are not separate blockchains at all. They are contracts on Ethereum that keep a balance sheet of who owns how many units.
• Decentralized exchanges. Contracts that hold pools of two tokens and let anyone swap between them at a price set by a formula.
• Lending. Contracts that let users deposit one asset as collateral and borrow another, with automatic liquidation if the collateral value falls too far.
• Collectibles. Contracts that record ownership of a unique item, such as a piece of digital art or a ticket.

The catch is that code does exactly what it says, not what its authors meant. A bug in a contract can be exploited, and because transactions on Ethereum are generally final, stolen funds are rarely recovered.

How Ethereum stays secure: proof of stake

Every blockchain needs a way for strangers to agree on which transactions happened and in what order. Bitcoin uses proof of work, where miners burn electricity racing to solve a puzzle.

Ethereum used proof of work for its first years too. That changed with an upgrade the community called The Merge, which ethereum.org says took place on September 15, 2022. Since then, Ethereum has run on proof of stake.

Under proof of stake, participants called validators lock up ether as a security deposit. According to ethereum.org, running a validator that proposes blocks requires committing 32 ETH. Validators take turns proposing new blocks and checking each other's work. If one tries to cheat, the protocol can destroy part of its deposit. Honest validators earn rewards.

The switch had a large effect on power use. Ethereum.org estimates the network's energy consumption dropped by about 99.95 percent after The Merge, because there is no longer a hardware race to win blocks.

For ordinary holders, staking is usually done through an exchange or a staking service rather than by running a validator directly. Those services add their own risks, including the chance that the provider fails or freezes withdrawals, and staking rewards generally count as taxable income in the US. Our crypto taxes guide covers how that works.

Gas fees: why using Ethereum costs money

Every action on Ethereum, from sending ETH to a friend to trading on an exchange contract, uses computing work on thousands of machines. The network charges a fee for that work, measured in units called gas and paid in ether.

A few practical points:

• Fees rise when the network is busy, because users compete to get their transactions included sooner.
• A simple transfer uses less gas than a complex contract interaction.
• Your wallet app will show an estimated fee before you confirm. Read it every time.

High fees during busy periods pushed many users toward so called layer 2 networks. These are separate systems that bundle many transactions together and then settle a summary on Ethereum. They usually cost less per transaction, but each one has its own design, its own bridges and its own risks, and moving funds between them and Ethereum adds steps where mistakes can happen.

How people actually use Ethereum

Holding ether

Some people simply buy ETH as a speculative asset, much as they might buy bitcoin. Its price can move sharply in either direction, and nothing here should be read as a prediction or a recommendation.

Using apps

Others use Ethereum apps directly: swapping tokens, lending, buying collectibles or holding stablecoins. To do that you need a wallet that can sign transactions. Our guide to crypto wallets explains the difference between a wallet an exchange holds for you and one where you control the keys yourself.

Building on it

Developers write contracts in languages designed for Ethereum and deploy them for a fee. Because the code is public, anyone can inspect it, which helps auditors and also helps attackers looking for weaknesses.

The risks worth understanding first

Ethereum is mature compared with most crypto projects, but using it still carries real risk:

• Price swings. ETH can lose a large share of its value quickly.
• Smart contract bugs. A flaw in an app you use can drain funds, even if Ethereum itself works perfectly.
• Approval traps. When you connect a wallet to an app, you may grant it permission to move your tokens. Malicious sites ask for unlimited permissions. Review and revoke approvals you no longer need.
• Lost keys. If you control your own wallet and lose the recovery phrase, nobody can restore access.
• Scams. Fake airdrops, impersonated support accounts and copycat token names are common. Our scam spotting guide walks through the warning signs.
• Irreversible mistakes. Sending funds to the wrong address or the wrong network usually cannot be undone.

A sensible approach for a beginner is to start small, use well known wallets, double check every address, and never type a recovery phrase into a website.

Where Ethereum fits in the bigger picture

Ethereum is best understood as infrastructure. It is the base layer that a large share of crypto applications, tokens and stablecoins are built on. Whether those applications prove useful at scale is still an open question, and regulators in Washington are still working out how many of them should be treated. You can follow those developments in our crypto coverage.

Frequently asked questions

Is Ethereum the same as ether?

No. Ethereum is the blockchain network. Ether, or ETH, is the currency used to pay fees and secure that network. People often use the names interchangeably, but the distinction matters when you read news about the technology versus the price.

Does Ethereum still use mining?

No. Since The Merge on September 15, 2022, according to ethereum.org, Ethereum has used proof of stake. Validators lock up ether instead of running mining hardware.

Why are some Ethereum transactions so expensive?

Fees are paid in gas and rise with demand. When many people try to use the network at once, they bid more to get included quickly. Complex contract actions also use more gas than simple transfers.

Do I need 32 ETH to earn staking rewards?

You need 32 ETH to run your own validator, per ethereum.org. Many people instead stake smaller amounts through exchanges or pooled services, which come with their own counterparty and tax considerations.