Bitcoin vs. Ethereum: the fundamental differences

Bitcoin and Ethereum often appear side by side, as if they were two versions of the same product. They are not. Both use a blockchain, a public record of transactions maintained by thousands of computers with no central owner, but each was built to answer a different question.

This article compares the two networks by their technical design, based on the original papers and each project’s official documentation, consulted on October 8, 2026. There is no price forecast or buy recommendation here. The goal is for you to understand what each system does, how it does it and where the risks lie.

The question each one set out to answer

Bitcoin. The paper that introduced Bitcoin, signed by Satoshi Nakamoto, has a title that already sums up its goal: a peer-to-peer electronic cash system, that is, from person to person. According to the whitepaper, the core problem was preventing double spending, the possibility of someone spending the same digital coin twice, without relying on a bank or another trusted intermediary. The network’s first block is dated January 3, 2009, according to the genesis block data on mempool.space.

Ethereum. The Ethereum whitepaper, attributed by ethereum.org to Vitalik Buterin and presented on the page as published in 2014, started from a different ambition: a blockchain with a full built-in programming language in which anyone could write programs. The paper specifically criticizes the limitations of Bitcoin’s scripting language. The main network went live on July 30, 2015, according to the official upgrade timeline. Ethereum.org itself warns that the original whitepaper no longer describes today’s Ethereum.

In our newsroom’s assessment, almost all the differences below stem from that starting point: Bitcoin optimizes for being a simple monetary system that is hard to change; Ethereum, for being a platform for running programs.

Side-by-side overview

Aspect	Bitcoin	Ethereum
Original goal	Electronic cash without an intermediary	Platform for running programs
Native coin	bitcoin (BTC)	ether (ETH)
Maximum supply	21 million BTC	No fixed cap
Consensus	Proof of work (mining)	Proof of stake since September 15, 2022
Time between blocks	About 10 minutes on average	12-second slots
Ledger model	Unspent outputs (UTXO)	Accounts with balance and code
Programming	Simple Script, deliberately limited	General-purpose smart contracts
Fees	Proportional to transaction size in bytes	Gas used × price per unit; part is burned

The details and sources for each row are in the sections below.

Monetary policy: fixed cap versus dynamic supply

The bitcoin.org FAQ states that only 21 million bitcoins will ever be created. Issuance happens with each block: the miner who produces it receives new coins, the so-called block subsidy, plus the fees from the included transactions, according to the developer glossary.

The pace of issuance is written in the code. In Bitcoin Core, the network’s reference software, the function that calculates the subsidy starts at 50 BTC per block and halves the amount every 210,000 blocks, which the code comment itself estimates at about four years. This is the halving, explained in detail in The Bitcoin halving. The most recent cut took place at block 840,000, recorded on April 20, 2024, according to the public block data on mempool.space, and reduced the subsidy to 3.125 BTC. On October 8, 2026, the network was at block 970,493, according to the same source. The next cut is expected at block 1,050,000; the date depends on the actual pace of blocks.

The whitepaper already anticipated what happens when issuance ends: once the predetermined number of coins is in circulation, miners’ compensation would come from fees alone. The topic is covered in depth in Why Bitcoin has a fixed supply.

Ethereum makes a different choice. The official ether page says that, unlike Bitcoin’s 21 million cap, ETH has a dynamic supply. Two mechanisms push in opposite directions:

• issuance. Validators receive new ETH as a reward. According to the page on The Merge’s impact on supply (last updated June 6, 2026), the amount issued per day depends on the total ETH staked. In the scenario used on the page, with 14 million ETH staked, issuance would be about 1,700 ETH per day, or 0.52% per year. That is a calculation for that scenario, not an up-to-date figure;
• burning. Since the London upgrade of August 5, 2021, part of every fee, the base fee, is destroyed and removed from circulation.

According to the same page, when a day’s burn exceeds issuance, the ETH supply shrinks; when it falls short, the supply grows. Neither outcome is guaranteed. It depends on network usage.

Consensus: energy versus ETH collateral

Consensus is the process by which thousands of computers agree on which transaction history is valid.

Bitcoin uses proof of work. Per the whitepaper, participants search by trial and error for a number that makes the block’s cryptographic hash begin with a certain number of zeros. Finding it is expensive; checking it is cheap. The valid chain is the one that has accumulated the most work, and the paper sums up the logic as “one-CPU-one-vote”. Difficulty adjusts every 2,016 blocks to keep the pace at about two weeks per cycle, according to the developer guide on the block chain. The process is covered in Bitcoin mining.

Ethereum also started with proof of work but switched to proof of stake on September 15, 2022, in the event known as The Merge. According to the official Merge page, the change cut the network’s energy consumption by about 99.95%. The same page clears up two misconceptions: the change did not lower fees and barely changed transaction speed.

In proof of stake, described in the technical documentation, blocks are validated by validators who deposit 32 ETH as collateral. Time is divided into 12-second slots, grouped into epochs of 32 slots. Anyone who acts dishonestly, for example by proposing two blocks in the same slot, is subject to slashing: they lose part or all of the deposited ETH.

Finality: when a transaction can no longer be undone

The two networks treat the question “when can I consider the payment complete?” differently.

In Bitcoin, security is probabilistic. The whitepaper calculates the probability of an attacker rewriting history and shows that it drops exponentially with each block added after the transaction. The bitcoin.org FAQ mentions that six confirmations are often considered as safe as waiting six months on a credit card transaction, but leaves the choice of threshold to each user.

In proof-of-stake Ethereum, there is explicit finality. Per the documentation, when validators representing at least two-thirds of the staked ETH vote on a pair of checkpoints, the older one becomes final. Reverting a finalized block would require attackers to accept losing at least one-third of all staked ETH.

Programmability: limited script versus smart contracts

Bitcoin records coins as UTXOs (unspent transaction outputs): each coin is the output of an earlier transaction, and each output carries a condition for spending it. That condition is written in Script, a language that, according to the transactions guide, was deliberately designed to be stateless and not Turing-complete, meaning no loops or jumps. The documentation presents this as an advantage: more predictable scripts that are simpler to secure.

Ethereum records accounts. According to the accounts documentation, there are two kinds: those controlled by private keys, belonging to people, and contract accounts, controlled by the code itself. A smart contract, per the official definition, is a program that runs on the blockchain, with functions and data at an address. By default it cannot be deleted, and interactions with it are irreversible. Contracts also cannot access real-world data on their own; they depend on services called oracles.

This programmable layer is what makes it possible to create tokens and applications on top of the network. The whitepaper page on ethereum.org cites, among the changes since 2014, the growth of decentralized finance (DeFi), NFTs and DAOs, organizations governed by contracts. An overview of these pieces is in What Ethereum is and how it works.

Fees: what you pay and why

In Bitcoin, the FAQ explains that the fee depends on the transaction’s size in bytes, not on the amount sent, and varies with demand for block space. In practice, the fee is the difference between what goes into and what comes out of the transaction, which goes to the miner.

In Ethereum, every operation consumes gas, a unit of computational effort. According to the gas documentation, the fee is the gas used multiplied by the price per unit, split into two parts: the base fee, set by the protocol and burned, and an optional tip to the validator. The fee is charged even if the transaction fails. Because contracts can run many operations, a complex interaction costs more than a simple transfer.

In both cases, the value of a fee in Brazilian reais (or any other currency) changes with network usage and with the coin’s price. Any published number ages quickly; check your wallet’s estimate at the time of the transaction.

Risks: what is shared and what is specific

The risks below are not exhaustive. In every case, the loss can be total.

Common to both networks:

• volatility. Bitcoin.org, on its Some things you need to know page, says bitcoin should be treated as a high-risk asset. The same reasoning applies to ether, whose value also swings sharply;
• irreversibility. A confirmed transaction cannot be undone by the network. Sending to the wrong address or to a scammer usually means a permanent loss;
• custody. Anyone who loses the private keys or recovery phrase of their own wallet loses access to the funds, with no one to turn to. Leaving them with a company shifts that risk to the company’s soundness and honesty;
• limited privacy. The records are public. Anyone can see an address’s balance and history;
• rule changes. Protocols evolve through upgrades. For Bitcoin, the developer guide describes how a disagreement can produce permanently separate chains;
• taxes and regulation. Each country has its own rules, and complying with tax obligations is the responsibility of whoever holds the assets.

More present in Ethereum:

• contract bugs. A contract with a programming error stays live and can be exploited. Using an application means trusting its code, not just the network;
• staking. Validators, or services that stake on behalf of others, can be slashed. The documentation describes losses ranging from less than 0.1% of the deposit to 100%, depending on how many validators are penalized at the same time;
• complexity. In our newsroom’s assessment, more features mean more points of failure: approvals granted to contracts, bridges between networks and third-party applications carry their own risks, on top of the risks of the main network.

Key takeaways

Bitcoin and Ethereum do not compete for exactly the same role. Bitcoin was designed as digital money with simple rules, scheduled issuance and a 21 million cap, secured by proof of work. Ethereum was designed as a programmable platform, with a supply that rises or falls with usage and, since 2022, secured by proof of stake. Before using either network, understand which problem it solves, how much you can lose without jeopardizing your finances and who holds the keys.