Replace-by-fee (RBF)

Replace-by-fee lets you resend an unconfirmed Bitcoin transaction with a higher fee so it confirms faster. Learn the rules and how wallets do it.

Bumping a stuck payment

If your transaction is stuck because the fee was too low, you can broadcast a replacement: a new transaction that spends at least one of the same inputs and pays a higher fee. Nodes swap the old one for the new one in their mempool.

The main rules

A replacement must:

• spend at least one of the same inputs (so the two conflict),
• pay a higher total fee than the original,
• pay extra enough to cover its own size at the node's minimum relay rate.

Signalling

Originally, a transaction had to opt in to RBF by setting a sequence number below 0xfffffffe (BIP 125). Since Bitcoin Core 28.0, nodes by default accept replacements whether or not the original signalled. Many wallets show a "bump fee" button for this.

What RBF means for receivers

An unconfirmed payment can be replaced, even with one that pays someone else. That's why merchants should wait for at least one confirmation for anything valuable.

How to bump a fee in practice

1. Find the unconfirmed payment in your wallet.
2. Choose "bump fee", "speed up" or "increase fee".
3. Pick a new fee rate above the current next-block estimate.
4. Confirm. The wallet broadcasts the replacement; the old version disappears from mempools.

How much higher?

The replacement must pay more in total and enough extra to cover its own size at the minimum relay rate. Wallets work this out for you.