How to speed up a stuck bitcoin transaction (RBF and CPFP)

A stuck bitcoin transaction is almost always a fee problem: you offered miners less per byte than others did, so your payment keeps getting skipped. You have three ways out: raise the fee with Replace-by-Fee (RBF), add a high-fee follow-up transaction with Child Pays for Parent (CPFP), or wait until it confirms or drops out. This guide explains how each works, which one you can use, and how to do it safely.

Why bitcoin transactions get stuck

When you send bitcoin, your wallet broadcasts the transaction to the network, where it waits in each node's mempool (memory pool) of unconfirmed transactions. Roughly every 10 minutes a miner builds a new block and, because block space is limited, fills it with the transactions that pay the most per unit of size. If you are new to how mining and blocks work, start with what is bitcoin.

• Fees are measured as a fee rate in satoshis per virtual byte (sat/vB), not as a flat amount. A transaction with many inputs is larger and needs a bigger fee for the same priority.
• When demand rises, for example during a price swing, the minimum fee rate that gets into the next blocks rises too. Transactions sent earlier at a low rate fall behind.
• Your wallet's fee estimate was a guess about the future. If the mempool filled up after you sent, the guess was too low.

You can check where you stand by pasting your transaction ID into a block explorer: it shows your fee rate and how it compares with the rates currently being confirmed.

Option 1: Replace-by-Fee (RBF)

RBF lets the sender replace an unconfirmed transaction with a new version of the same payment that pays a higher fee. Nodes and miners drop the old version and keep the new one, because it pays more. The replacement spends at least one of the same coins, so only one of the two can ever confirm.

How to do it:

1. Open the pending transaction in your wallet and choose Bump fee, Increase fee or Speed up (the name varies; Electrum, Sparrow and Bitcoin Core all support it).
2. Pick a new fee rate a little above what is currently confirming.
3. Check the destination address and amount on your screen or hardware wallet, then sign and broadcast.

Rules to know: the replacement must pay a higher total fee and a higher fee rate than the original. Older wallets signal "replaceable" transactions under BIP 125; since Bitcoin Core 28.0 (October 2024) nodes relay replacements by default even without that signal, though your wallet still has to offer the button. Only the sender can use RBF, so if an exchange or merchant sent the payment, ask them.

Some wallets also offer Cancel, which is RBF that sends the coins back to your own address with a higher fee. It only works while the original is unconfirmed.

Option 2: Child Pays for Parent (CPFP)

CPFP speeds up a stuck transaction by spending one of its outputs in a new "child" transaction with a high fee. Miners can only take the child if they also include the parent, so they judge the two as a package by their combined fee rate.

• The receiver can use CPFP on the output paid to them, which is useful when the sender won't or can't bump.
• The sender can use CPFP on their own change output if RBF is not available.
• In Electrum the option is called Child pays for parent; Sparrow and other advanced wallets offer it too.

CPFP costs more than RBF, because you pay for a second transaction. A worked example: a 200 vB parent paid 2 sat/vB (400 sats) and the market is now confirming at 12 sat/vB. With a 150 vB child, the package is 350 vB, which needs 4,200 sats in total at 12 sat/vB. The child must therefore pay about 3,800 sats, roughly 25 sat/vB on its own. With RBF, the same 200 vB payment at 12 sat/vB would cost 2,400 sats.

Option 3: Accelerators or waiting

If neither the sender nor the receiver can bump the fee, you have two fallbacks.

• Transaction accelerators. Some services and mining pools, such as mempool.space's Accelerator or ViaBTC's accelerator, will prioritise a transaction for a fee or within limited free slots. They only help with the share of blocks those pools mine, and you should only use them on their official sites: fake "accelerators" are a common scam.
• Waiting. Fees often fall at weekends or after a busy spell. If the transaction never confirms, nodes drop it from their mempools; Bitcoin Core does so after two weeks by default, or sooner if its mempool is full. Your wallet then shows the coins as spendable again, and you can resend with a proper fee. Some nodes may still hold the old version, so resending with RBF is safer than simply sending a new transaction.

Stay safe when bumping a fee

• Keep your wallet software updated, and download it only from the official site.
• If your wallet relies on third-party servers, as light wallets do, prefer a server you trust or your own node.
• Never share your seed phrase with anyone offering to "unstick" a transaction. No legitimate service needs it; see our hardware wallet guide for how signing works.
• For frequent small payments, the Lightning Network avoids on-chain fee spikes for each payment.

How to avoid stuck transactions next time

1. Look at current fee rates on a block explorer before you send, especially for urgent payments.
2. Use a wallet that marks transactions as replaceable and has a bump-fee button.
3. Consolidate many small coins when fees are low, so future payments are smaller in vbytes.
4. If you are withdrawing from an exchange, note that it sets the fee; check its withdrawal fee and timing before you rely on a deadline.