RBF vs CPFP: How to Speed Up a Stuck Bitcoin Transaction

When a Bitcoin transaction is stuck because the fee was too low, you have two ways to speed it up: Replace-by-Fee (RBF) and Child-Pays-for-Parent (CPFP). They solve the same problem from opposite ends. The simple rule: use RBF when yousent the transaction, and CPFP when you're receivingit. Here's how each works and when to reach for which.

Replace-by-Fee (RBF): bump your own transaction

RBF lets you replace a stuck, unconfirmed transaction with a new version of the same transaction that pays a higher fee. The replacement out-bids the original and jumps back up the queue; miners confirm the new one and the old one is discarded.

When you can use it

• →You sent the transaction — RBF only works on transactions you created.
• →It was flagged as RBF-enabled when you broadcast it. Many wallets enable this by default; some let you toggle it per send.
• →It's still unconfirmed. Once it confirms, there's nothing to replace.

How to do it

In a supporting wallet, open the pending transaction and look for “Bump fee,” “Increase fee,” or “Speed up.” The wallet rebuilds the transaction with a higher rate and rebroadcasts it. Check a live trackerfirst so you bump to a rate that's actually competitive right now.

Child-Pays-for-Parent (CPFP): pull a transaction through

CPFP is for when you can't edit the stuck transaction — most often because someone sentBitcoin to you and it's stuck. You create a new transaction (the “child”) that spends the unconfirmed incoming output, and you attach a high fee to it. Because a miner can only collect the child's juicy fee by also confirming its unconfirmed parent, they pull both into a block together.

When you can use it

• →You're receiving a stuck transaction (you can't RBF someone else's send).
• →RBF wasn't enabled on a transaction you sent, but you control one of its outputs.
• →Your wallet supports it — CPFP is more advanced and not in every wallet.

The catch

The child's fee has to be high enough to cover bothtransactions' share of block space, so CPFP can get expensive. It's a rescue tool, not a routine one.

RBF vs CPFP at a glance

• →Who controls it: RBF — the sender. CPFP — usually the receiver (or anyone who controls an output).
• →What it does: RBF replaces the transaction. CPFP adds a second transaction that drags the first along.
• →Requirement: RBF needs the original to be RBF-enabled. CPFP needs a spendable unconfirmed output.
• →Cost: RBF is usually cheaper and cleaner. CPFP pays for two transactions' worth of space.
• →Best for: RBF — “I sent it and it's stuck.” CPFP — “I'm waiting on a stuck incoming payment.”

Better than fixing: avoid it

• →Check the live rate before sending — see what a good fee is right now.
• →Leave RBF enabled so you always have the easy fix available.
• →Send during quiet windows — see the cheapest time to send.

The bottom line

RBF and CPFP are the two safe ways to rescue an underpaid Bitcoin transaction. Bump your own send with RBF; pull a stuck incoming payment through with CPFP. Both keep your coins fully under your control — and most of the time, checking the live fee before you send means you'll never need either one.

Send at the right rate the first time with the SatSaver tracker. Mempool data from mempool.space.