CPFP (Child Pays For Parent) – Bitcoin Fee Bumping Explained

When working with CPFP, Child Pays For Parent, a fee‑bumping method that lets a high‑fee child transaction push an older low‑fee parent transaction through the Bitcoin mempool. Also known as fee bumping, it’s a lifeline for stuck payments and a tool for traders who need speed without re‑broadcasting the original transaction.

CPFP sits inside a web of related concepts. A Bitcoin transaction, a record of value transfer that sits in the mempool until miners pick it up carries a fee that influences its priority. When that fee is too low, the transaction can linger for hours or days. That’s where Replace‑by‑Fee (RBF), a protocol that allows the sender to replace an unconfirmed transaction with a newer one that pays a higher fee comes in. RBF and CPFP are different tricks for the same problem: getting a transaction confirmed quickly. RBF changes the original transaction, while CPFP creates a new child that pays a higher combined fee, urging miners to include both. Understanding the mempool, the pool of pending Bitcoin transactions awaiting confirmation is key, because fee competition happens there. The higher the total fee of the parent‑child pair, the more attractive the package becomes for a miner looking to maximize earnings per block.

Why CPFP matters for traders and everyday users

If you’ve ever watched a transaction sit idle, you know the frustration. CPFP lets you attach a fresh, higher‑fee child transaction without altering the original payment details—a boon for people who can’t or don’t want to resend the whole thing. It also works well with Lightning‑Network channel funding: you can fund a channel with a low‑fee on‑chain transaction, then use CPFP to speed up the opening if the network gets busy. Miners benefit, too, because they get a larger total fee for a single block slot, which can improve overall network efficiency. The strategy also ties into broader market dynamics—when Bitcoin’s price swings, fee markets tighten, and users increasingly rely on techniques like CPFP and RBF to stay on‑time with trades.

Below you’ll find a curated set of articles that dive deeper into CPFP, related fee‑bumping tactics, mining economics, and how these tools fit into the larger crypto landscape.