What is UTXO (Unspent Transaction Output)?
Bitcoin tracks ownership as a set of unspent transaction outputs (UTXOs). A wallet's balance is the sum of all UTXOs it can spend. Each transaction consumes one or more UTXOs and produces new ones, preventing double-spending by construction.
Why UTXO (Unspent Transaction Output) matters
Understanding UTXO (Unspent Transaction Output) is part of building a solid mental model of how Bitcoin, blockchain and Web3 systems actually work. Concepts in the Bitcoin category sit at the foundation of the broader stack — get them right and the rest is far easier.
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Related terms
- Transaction — A signed instruction that updates the blockchain state.
- Address (Bitcoin / Crypto Address) — A public destination for receiving cryptocurrency.
- Double Spend — Attempting to spend the same coin twice.
More bitcoin terms
- Block Header — The metadata at the top of each block.
- Block Reward — New coins paid to the miner of a block.
- Difficulty — A parameter that controls how hard it is to mine a block.
- Halving — The scheduled 50% cut in Bitcoin's block subsidy.
- Hash Rate — The total computational power securing the network.
- Mining — Producing new blocks by performing Proof of Work.
- Nakamoto Consensus — Bitcoin's consensus rule: follow the chain with the most work.
- Nonce — The number miners change while searching for a valid hash.
Keep exploring
Continue with the full blockchain glossary — 136 terms in total — or read the developer blog and FAQ for deeper context.