Bitcoin and Ethereum both let a network verify transfers without a bank approving each payment. Ethereum adds a more general environment for programs that hold assets and respond to transactions. That flexibility makes useful arrangements possible, while adding risks in code, external data, and the way applications connect.
The practical comparison starts with one question: what do you want the network to enforce? A payment needs valid authorization and funds that have not already been spent. A fundraising arrangement also needs rules for contributions, deadlines, release, and refunds. Those extra rules create extra things to inspect.
The thumbnail’s wallets and branching arrows illustrate this distinction. They are not a diagram of where coins physically reside, or evidence that Bitcoin payments cannot go wrong.
A shared record, with different jobs
A digital file can be copied without depriving its owner of the original. A payment system cannot accept two incompatible spends of the same funds. Both networks use shared transaction records and validation rules to address that problem.
Bitcoin’s transaction guide explains the details through unspent transaction outputs, or UTXOs. A transaction spends earlier outputs and creates new ones with spending conditions. A wallet’s displayed balance adds up outputs it can spend; it does not count coins stored inside the app.
A hypothetical payment makes that concrete. If you control one output worth 0.01 BTC and want to pay 0.003 BTC, a transaction can create a recipient output and a change output for you, leaving a fee. The original output is consumed in full. Copying that transaction does not make it spendable twice.
Signatures prove authorization without publishing the private key. Bitcoin also has programmable spending conditions, including requirements for multiple signatures. Calling it “money without code” misses this existing functionality. Our explanation of copied Bitcoin data follows the output model in more detail.
Ethereum adds programs with persistent state
Ethereum’s smart-contract documentation describes a contract as code and stored data at a blockchain address. A transaction can call a function, and execution changes the shared state according to the program’s rules. Contracts can also call other contracts.
Consider a hypothetical fundraiser. A contract records contributions, a target, and a deadline. After the deadline, a transaction requests release if the target was reached, or a refund if it was missed. The exact behavior depends on the code: who may request release, how contributions are counted, and which conditions allow withdrawal.
A deadline does not make the program wake up by itself. Execution still needs a triggering interaction. The useful automation is the response once that interaction occurs.
Following a programmed rule also differs from deciding whether a project deserves funding. In this example, the contract could verify the recorded contribution total, while leaving project quality entirely outside its task. The word “smart” should not persuade you that the software can make that judgment.
Outside facts bring trust back into the picture
A fundraiser can use contributions already recorded onchain. A payout tied to a canceled flight needs information from outside the blockchain. The contract cannot directly observe the departure gate.
Ethereum’s oracle guide explains how external information is supplied for contracts to consume. An oracle bridges that gap, but its data source, update process, and trust model matter. Using several providers changes the design; it does not eliminate the need to inspect it.
For the hypothetical flight payout, ask what counts as cancellation, who reports it, and what happens if the report is late or wrong. Those questions remain even if every computer executes the payout code identically.
Agreement about the information received is different from proof that it accurately describes the world. Every validator could execute the payout rule consistently while the flight report was wrong. Our smart-contract walkthrough follows that distinction from a deposit through external data and authority over the code.
Gas measures work, and failed execution can cost money
Ethereum meters execution using gas. As its gas and fees documentation explains, gas measures computational effort, while the price per unit determines what that work costs. Mainnet fees are paid in ETH. Gas is not a separate asset that you must purchase.
A hypothetical bill separates work from its unit price:
50,000 gas × 10 gwei per gas = 500,000 gwei = 0.0005 ETH.
This is arithmetic, not a current fee quote. More work at the same unit price increases the bill. A higher unit price for the same work also increases it. Neither change requires sending a larger amount to the recipient.
An included transaction that executes and reverts can still consume gas. Reversing the intended state changes does not undo the computation already performed. A transaction rejected before execution is a different case.
Bitcoin also charges transaction fees, but transferring a larger BTC amount does not automatically require a larger fee. Both networks have capacity constraints; the currency amount alone is a poor guide to processing cost.
Block production uses different resources
Bitcoin’s mining guide describes hardware repeatedly hashing a block header while seeking a result below a target. A successful result lets the miner propose a block. The work makes changing transaction history costly, but a miner’s proposal still has to satisfy validation rules.
Ethereum instead uses proof of stake. Validators commit ETH, check blocks, and participate in proposals and votes. Certain conflicting proposals or votes can cause staked ETH to be destroyed. Ordinary missed duties and punishable violations should not be treated as the same event.
These mechanisms address how the network agrees on history. Neither reviews a fundraiser’s business plan or makes an oracle’s report true. Changing the consensus mechanism does not remove application-level dependencies.
Supply rules and user safety answer separate questions
The Bitcoin FAQ describes declining issuance toward a maximum of 21 million BTC under the existing rules. It also explains that price depends on supply and demand. A supply limit therefore does not guarantee stable purchasing power or a profitable investment.
Ethereum’s fee system burns the base-fee portion, and its validator system pays rewards. Those mechanisms are different from Bitcoin’s capped issuance schedule. The comparison helps explain network design; it does not rank future investment returns.
For a payment, inspect the recipient, authorization, and custody arrangement. For a contract interaction, add the program’s behavior and any external information it depends on. If you use another execution layer, inspect that layer’s assumptions too; our Base explanation follows one such arrangement.
Ethereum’s flexibility matters when the extra rules serve a specific purpose. The decision becomes clearer when you can name that purpose, identify each dependency, and explain what would happen if one failed.
