Note from the author: Our previous guide explains how to avoid stuck transactions: by paying the correct fee for the current network circumstances. This guide explains how to deal with stuck transactions and reduced fees. We recommend reading these guides in order, since the first one covers some foundational concepts. This guide assumes some familiarity with wallet operations—particularly finding a transaction ID (txid) and inputs and outputs. Bitcoin’s rocket ride has created a lot of believers and disproven a lot of critics. Bitcoin’s futures are now trading on traditional markets, and Bitcoin ranks 2nd in Google searches for 2017. So it’s clear that Bitcoin is succeeding beyond the expectations of all but the most optimistic early adopters. But it’s not all good news! Exchanges are buckling under the pressure of new-user registrations (which are reportedly a higher order of magnitude than last year). Even more concerning: The Bitcoin network’s rapid growth has brought it to the limits of its non-upgraded scaling capacity. The Problem: High Fees and Slow Transactions If you sent a Bitcoin transaction in early December, chances are that you paid a really high— even record-high—transaction fee. And if you didn’t, then perhaps you experienced a delayed transaction. Here’s the way Bitcoin works: a limited number of transactions can be confirmed in each block. As you probably know, miners produce a new block every 10 minutes or so, and transaction fees are the “bribes” that convince miners to include transactions in their new blocks. An included transaction is known as a confirmation. When the price is really volatile, many people frequently try to send transactions at the same time. So competition for this limited block space drives up fees. The higher the fee attached to a transaction, the greater the chance that it’ll be confirmed in the next block. Johoe’s Bitcoin Mempool Statistics site gives a visual representation of the number of unconfirmed transactions over time, and across various fee levels. It’s a great resource. Note: As the mempool fills, new bands appear and widen, and fees are driven up. As the mempool clears, the uppermost fee ranges tend to be processed and closed first, as they represent the most profitable transactions for miners. This economic process is referred to as the fee market. Necessary Concepts We know that you’re probably impatient to fix your transaction, but doing so requires some knowledge of how Bitcoin works. We’ll try to keep the technobabble to a minimum… 1. The Mempool The graphic above depicts what’s known as the memory pool (mempool): the set of unconfirmed transactions that are waiting to be entered into the blockchain. The mempool exists in the memory (RAM) of all Bitcoin full nodes (i.e., computers that are a part of the Bitcoin network). Note that different nodes have different versions of the mempool, depending on which transactions they know about and remember. So each mempool is different for each node. If a transaction is not confirmed for a long period of time, it will eventually fade from the node’s mempool. The current default timeout is 72 hours. (Previously, it was 2 weeks.) But nodes may set their own duration. The transactions with the lowest value will also be dropped from the mempool, as higher fee transactions are entered. It’s possible that a certain node (probably your own) will never forget about your transaction, and may even occasionally rebroadcast it, which reminds other nodes about it. 2. Transaction IDs Regardless of whether it’s confirmed or unconfirmed, every Bitcoin transaction (tx) is assigned a unique identifier, which is known as a transaction ID (txid). Your wallet will report this txid. You can consult the wallet’s documentation if you’re unsure about how to access it. By copying and pasting the txid into any block explorer, you’ll get more info about the transaction. Note: Your txid will be needed for some of the solutions covered below. 3. Satoshis per Byte (sat/B) Of course, satoshis are the smallest units of bitcoin.