> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/wiki/transactions-and-utxos/bitcoin-transactions/change.md). # Change 1. Introduction When a UTXO is spent, it must be consumed entirely. If the value of the UTXO is greater than the amount being spent, then the difference in the amount must be allocated to a new address that the spender owns; this is a change address. 2. Example 1 In a standard payment scenario, the sender consumes a single UTXO, paying the spending amount to the receiver's address, then receiving the change into a new address that they control to take advantage of privacy. In [this example](https://whatsonchain.com/tx/d0033a539a426de7142f4b230328c84306b6ebc1c985515d522a411c397522df), we can see that address 197vdcD73wQF5FviYXXgv6cXJBibc9phdq held a UTXO containing 47,097 Satoshis. The sender paid 10,000 Satoshis to 1C7UVhVnspkxot82j6ooMxUUFEWy4Pj1tc and received 36,871 Satoshis as change into address 1LNq2ZePCj2mycctrvQqBVnTLeaJeyDeR4. The difference of 226 Satoshis was paid as Transaction fees to the Miner who found block 605,046. 3. Example 2 In [this example](https://whatsonchain.com/tx/defaaec6d8687a27da68d2bd445dac9c1333c4460246309070a5a3cf40f3d6f0), we can see more clearly that the difference between the input and output is the mining fee. In this transaction a UTXO held by address 13N2c1uxZee4LYGruhWED6K4P4D8Ncmepq is spent in a transaction that writes a message onto the ledger in an OP\_RETURN output, and receives the original amount minus the 276 Satoshi mining fee back into the same address. 4. Consolidating UTXOs In some cases, the spender may have many UTXOs that they would like to consolidate. In this situation, the only output is their 'change' address where the total amount, less mining fees is sent. These 'consolidation transactions' have the added benefit of reducing the size of the UTXO set, shrinking the database that all nodes maintain. While the computation for processing these inputs could be expensive, it is envisaged that the savings in storage will encourage Miners to potentially process these types of transactions for a lower fee. An example can be found (). 5. Attribution This content is based on content sourced from under [Creative Commons Attribution 3.0](https://creativecommons.org/licenses/by/3.0/). Although it may have been extensively revised and updated, we acknowledge the original authors. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://hub.bsvblockchain.org/wiki/transactions-and-utxos/bitcoin-transactions/change.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.