The BTC balance in Core shows the available balance only, therefore if a user has a UTXO being used for an unconfirmed transaction, the rest of the funds associated with the UTXO will not be displayed in the UI until the transaction is complete.
NOTE: The remaining funds are safe and will remain in Core once the transaction is complete.
For example: if someone has a $20 bill and needs to pay $5 for a coffee, they must hand over the entire $20 bill to the cashier and wait for the change ($15) to be handed back to them.
With UTXOs, the basic principle is the same.
If a user funds their Bitcoin address with 1 BTC in a single transaction and wants to send .25 BTC later on, the UI will reflect the entire balance changing until the transaction is confirmed. To learn more about UTXOs and how they work, please refer to this article.
For any additional questions, please view our other knowledge base articles or contact a support team member via the chat button. Examples are for illustrative purposes only.