UTXO (Unspent Transaction Output)
An output of an earlier transaction that hasn’t been spent yet – like a single banknote in your wallet. Bitcoin has no account balances: your balance is the sum of all the UTXOs you can spend with your keys.
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UTXO stands for unspent transaction output: an output of a transactionGlossaryTransactionA signed message that transfers bitcoin from existing outputs (UTXOs) to new outputs. It only counts as confirmed once it is in a block – and after that it can practically no longer be reversed.On the learning path: Stage 5 · Step 4 – First withdrawal →In the glossary → that hasn’t been spent yet. Each output can be used exactly once as the input of a new transaction – after that, it is spent.[1]
Like banknotes in a purse
If you once received 300,000 sats and later 200,000 sats, your wallet holds two ‘notes’. The app only shows the total: 500,000 sats. If you pay 400,000 sats, the wallet spends both notes in full and sends the rest, minus the fee, back to an address of your own as change.
Why it matters
- Fees: every input makes a transaction larger and therefore more expensive. Many small UTXOs – for example from weekly withdrawals from a savings plan – cost more to spend than a few large ones.
- Privacy: if a transaction combines several UTXOs, observers can see that they probably belong to the same person. The whitepaper already points this out.[2] More in Privacy with Bitcoin.
- Coin control: some wallets let you choose which UTXOs to spend – which helps with fees and privacy.
Bitcoin transactions & fees shows how inputs, outputs and fees work together.
Related terms
These terms are closely connected.
- This termUTXO(Unspent Transaction Output)
- TransactionA signed message that transfers bitcoin from existing outputs (UTXOs) to new outputs. It only counts as confirmed once it is in a block – and after that it can practically no longer be reversed.
- Transaction fee (network fee)The amount a Bitcoin transaction pays to the miner. It depends on the transaction’s size in vbytes and the fee rate offered – not on the amount you send.
- Wallet (Bitcoin wallet)Software or a device that manages your private keys, generates receiving addresses and signs transactions. The bitcoin itself isn’t in the wallet but on the blockchain – the wallet holds the access to it.
- Bitcoin addressA string of characters like ‘bc1q…’ that someone can send bitcoin to. It is usually derived from a public key, can be shared without risk to your funds and should be generated afresh for every payment.
Explained in depth
These articles go into more detail:
- Deep dive · Stage 1Transactions & feesUTXOs, the mempool, sat/vB and confirmations: what happens when you send bitcoin, how the network fee arises and what helps with stuck payments.
- Deep dive · Stage 5PrivacyBitcoin is pseudonymous, not anonymous. How chain analysis works, what your exchange and the tax office know about you and how to protect your privacy legally.
- Stage 5 · Step 4First withdrawalSending bitcoin from an exchange to your own wallet: check the address, send a test amount, proof of ownership under the Travel Rule, whitelist, confirmations.
More from „Technology“
Sources2 sources · 2 publishers
The superscript numbers in the text refer to these sources.
- Bitcoin Developer Guide: Block Chain – bitcoin.org Developer Documentation (accessed 28/09/2026)
- Bitcoin: A Peer-to-Peer Electronic Cash System – Satoshi Nakamoto, 31.10.2008 (accessed 28/09/2026)
This entry is for education only and is not investment, tax or legal advice.