A Bitcoin transaction takes coins you previously received (inputs), assigns them to one or more destination addresses (outputs), and is signed with your private key. You broadcast it to the network, it waits in the mempool, and a miner includes it in a block. After that it has one confirmation; each later block adds another. Once confirmed, it cannot be altered or reversed by anyone.
Inputs, outputs and change
Bitcoin does not have "account balances" in the usual sense. Your wallet tracks discrete chunks of previously received bitcoin (called UTXOs). To pay someone, your wallet selects enough of those chunks to cover the amount plus the fee, sends the payment amount to the recipient’s address, and sends the leftover back to a change address it controls.
This is why a wallet showing "1.0 BTC" might build a transaction with several inputs and two outputs (recipient + change).
The lifecycle of a transaction
- Create & sign. Your wallet builds the transaction and signs it with your private key.
- Broadcast. It is sent to nodes, which check it and relay it.
- Mempool ("pending"). It waits with other unconfirmed transactions. A higher fee generally means a shorter wait.
- Mined. A miner includes it in a block (about every 10 minutes). Now it has 1 confirmation.
- Confirmed. Each new block on top adds a confirmation. Many services treat 3–6 as final.
What "pending" actually means — and what you can do
"Pending" means the transaction is valid and broadcast but not yet in a block. The coins have left your control (they are committed to that transaction) but have not yet fully arrived. Options, all initiated by the original sender:
- Wait — it may confirm when the mempool clears.
- Replace-by-fee (RBF) — rebroadcast the same transaction with a higher fee, if it was flagged replaceable.
- Child-pays-for-parent (CPFP) — spend the change output in a new high-fee transaction to incentivise miners to confirm both.
A third party cannot "release", "accelerate for a fee paid to them", or "redirect" your pending transaction. Be cautious of any service or individual offering to do so.
Key facts
- Bitcoin uses inputs and outputs (UTXOs), not account balances.
- A transaction usually has a "change" output back to yourself.
- The fee is set by you/your wallet and paid to the miner of the block.
- 1 confirmation = included in a block; more confirmations = harder to reverse.
- Confirmed transactions are permanent and cannot be edited or cancelled.
Risks and limitations
- Sending to the wrong address is irreversible.
- Too low a fee can leave a transaction pending for hours or days.
- Address-swapping malware can replace a pasted address — verify the first and last characters.
- Some services claim to "unstick" or "reroute" pending transactions for a fee. Only the sender can use RBF or CPFP; no third party can act on your transaction directly.
FAQ
Why does my wallet show a "change" transaction?
How many confirmations is "safe"?
My transaction is stuck. Can a website speed it up for a fee?
Can the recipient send it back?
Sources
Related topics
This guide is educational information about how cryptocurrency technology works. It is not financial, investment, legal or tax advice. Cryptocurrency involves risk, including the permanent loss of funds. See our editorial policy and methodology.