This page needs JavaScript to create the graphs and dynamically load the mempool data from the server.
This page displays the number, fee, or weight of the unconfirmed transactions, also known as the transactions in the mempool (the transactions that haven't been written to the block-chain yet and kept in the volatile memory). It gives a real-time view and shows how the mempool evolves over the time. The transactions are colored by the amount of fee they pay per virtual bytegas price they pay. The data is generated from my full node and is updated every minute. Note that in decentralized cryptocurrencies there is no global transaction mempool; every node keeps its own set of unconfirmed transactions that it has seen. The mempool is also cleared when I reboot my node.
The data is separated into different fee levels given in satoshi per bytescorresponding to the gas price. The lowest colored stripe is for transactions that pay the lowest fee. Higher fee transactions are stacked on top of it. Since miners prefer high fee transactions, a new block usually only removes the top-most 1 MB worth of transactons from the queue. If a colored stripe persists over several hours without getting smaller, this means that transactions paying this amount of fee are not confirmed during this time, because there are higher paying transactions that take precedence.
The horizontal axis is time and you can choose the range from the last 2h to all. The vertical axis of the chart can be switched between count, fee, and weight. In the weight chart the height of the graph reflects the total transaction sizegas limit instead of the number of transactions. If a stripe on the weight chart is much bigger than on the count chart, the transactions in this stripe are largermore computation demanding than the average. Similarly, in the fee chart, the height reflects the total amount of fee the pending transactions pay.
You can click on some fee level in the legend to hide all fee levels below that level. This way you can see better how many transactions are competing with that fee level.
Note that sizes include the segwit discount. This means that the graphs show virtual byte (weight divided by four). For segwit transactions, the real size of the transaction is a bit larger than the virtual size. A block will always take at most 1 vMB from the mempool, even if it is bigger than 1MB, and the weight diagram shows the size in vbyte (with the segwit discount included). The segwit discount is also included when computing the fee level for a transaction. In case a transaction pays exactly the fee that defines the boundary between stripes, it is included in the higher stripe. Free transactions are not included, even if they make it into the mempool.
The default mempool of a Bitcoin node is 300 MB, but the size is computed differently: there is no segwit discount and small transactions take more space in the mempool than they take when they are written into a block. Therefore, the default limit of 300 MB corresponds to 50-120 vMB, depending on the shape of the transactions.
Note that transactions that are dependent on lower fee transactions are put in the lower fee stripe. The top-most fee stripe contains only the transactions that pay the highest gas price and that can be mined, so miners will usually choose these transactions first. The statistics shows the maximum gas usage and the maximum gas price for the transactions; they may use less gas and pay less fee when they are mined, depending on the exact computations performed and the base fee at the time. The maximum miner tip is not considered at all in this statistics. Some very high gas transactions are excluded, since they distort the statistics and cannot be easily mined.
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FAQs
There are currently about 52,600 unconfirmed Bitcoin transactions. Mempool weight (the size of the data contained in the mempool) is around 222 vMB. Bitcoin Core's default maximum mempool limit is 300MB. All this begs the question: At what point does this become a problem?
What is the Bitcoin mempool queue? ›
The Bitcoin mempool, short for memory pool, is essentially a waiting area for all unconfirmed Bitcoin transactions. Think of it as a virtual queue where all the transactions wait to be picked up and included in the blockchain. Every time someone initiates a Bitcoin transaction, it first lands in the mempool.
How long can a transaction sit in mempool? ›
If a transaction is small, or if the network is congested at the moment, some transactions might be stuck in the mempool for up to 72 hours. After that, the transfer is cancelled, and all funds are returned to the crypto wallets of respective owners.
What is mempool in blockchain? ›
A mempool (a contraction of memory and pool) is a cryptocurrency node's mechanism for storing information on unconfirmed transactions. It acts as a sort of waiting room for transactions that have not yet been included in a block.
What is the average size of mempool? ›
Although there is no maximum size, nodes can set size limits for mempools. This limit is usually 300MB. Once the mempool reaches this limit, nodes may allocate a minimum transaction fee. Any transactions that do not meet this limit will be removed from the mempool.
What is the largest block size in Bitcoin? ›
Average Bitcoin block size & limit
The largest block, 3.9MB, was a majorly “Ordinal” block — an image of a bald, bearded Taproot Wizard, and just 63 transactions.
What is does a full mempool mean? ›
— A mempool is a blockchain node's waiting room for queued and pending transactions. — There isn't just one mempool for a blockchain, but many – one for each node on the network. — A transaction is only included in a block on the chain after it has been verified and approved in the mempool.
How to speed up a Bitcoin transaction? ›
If you have sent a transaction that is taking a long time to confirm, you can speed it up by using our increase fee feature. This resends your unconfirmed transaction with a higher fee. Bitcoin miners prioritize transactions with higher fees when selecting transactions to include in a block.
How many confirmations does mempool need? ›
When a transaction is included in a block, it is removed from the mempool and considered confirmed. However, this transaction only has one confirmation. It is generally considered a best practice to wait until a transaction has between two and six confirmations before considering it irreversible.
Can a BTC transaction be stuck forever? ›
If new transactions pay higher fees than you, your transaction could get stuck pending indefinitely, as it will constantly get moved to the back of the line.
You have several options if your transaction is stuck in the Bitcoin mempool. First, you can wait it out. Given sufficient time (usually 24 to 48 hours), your transaction will be sent back to your wallet if a miner had not yet added it to any new blocks.
Do all nodes have the same mempool? ›
“A mempool (short for "memory pool") is the queue of pending and unconfirmed transactions for a cryptocurrency network node. There is no one global mempool: every node on the network maintains its own mempool, so different nodes may hold different transactions in their mempools.”
Where is the Bitcoin mempool stored? ›
Every individual node within the blockchain maintains its own mempool that acts as a repository for the series of transactions that it has checked and validated. This means that a blockchain has as many mempools as there are nodes. In simpler terms, a mempool stores unconfirmed transactions as individual transactions.
What is Bitcoin mempool data structure? ›
At the code level, the mempool is essentially implemented as an indexed data structure, where the keys are the transaction IDs (txids), and the values are the transactions themselves. Bitcoin Core, for instance, primarily uses C++ data structures like std::map and std::set for indexing transactions and UTXOs.
How many bitcoins does mempool have? ›
The default mempool of a Bitcoin node is 300 MB, but the size is computed differently: there is no segwit discount and small transactions take more space in the mempool than they take when they are written into a block.
How big is the Ethereum mempool? ›
Every node has a mempool present in it. mempool has default size of 300 MB and every node is independent of including a transaction to its mempool.
How large is the Bitcoin source code? ›
In early years Bitcoin* only had about 3k lines of source code, as described by Greg Maxwell. Currently, the Bitcoin Core source code contains more 100k lines of code which is roughly equivalent to Monero.
How big is the Bitcoin block virtual size? ›
Virtual Bytes (vBytes, vB)
But using virtual bytes makes it easier to compare the fee rate of new segwit transactions with the fee rate of legacy transactions (which had previously used sats-per-byte). A legacy transaction will be the same size in bytes as it is in vbytes. A block can hold 1,000,000 virtual bytes.
