UTXO (Unspent Transaction Output)

Category: science

The accounting model used by Bitcoin where data is stored as a collection of unspent coin balances rather than account balances.

Unlike traditional account-based systems (like Ethereum or bank ledgers), Bitcoin does not track user accounts. A user’s wallet balance is calculated by scanning the blockchain for all unspent outputs (UTXOs) locked to their public keys. Every transaction destroys old UTXOs and prints new ones as outputs, including your change.

Common Examples

• Our local indexer script optimized its UTXO database cache to speed up the wallet balance retrieval times across our cluster.
• When you send a payment, your wallet combines multiple UTXO inputs to create the exact transaction total, leaving a new UTXO for the remainder.