Ever wondered what happens to your Bitcoin transaction before it is confirmed? It is added to a waiting room with several other unconfirmed transactions. This waiting room is called a mempool and it is an integral part of the Bitcoin mining process. A mempool or a memory pool is a mechanism for storing information on unconfirmed transactions. These transactions have been verified but have not yet been included in the blockchain.
Transactions are not added to a blockchain as soon as you make a payment. They are first sent to peer nodes for verification. Each node verifies the cryptographic signatures, checks if the funds are available, etc. Once the checks are done, the transaction is again broadcasted to nearby nodes. The goal is to send the transaction data to as many nodes as possible. This can help the nodes reach a consensus regarding the validity of a transaction.
If the transaction is invalid, then a node would simply drop it. This can happen if the sender has an insufficient balance in their wallet or the recipient’s public key is invalid. On the other hand, if a node is able to deem that a transaction as valid, it will be moved to the mempool, where a mining node can pick it up and package it into a block.
What happens to your transaction once it reaches the mempool?
In a utopian world, a miner will pick up your transaction as soon as it reaches the mempool and add it to the blockchain in 10 minutes (the block time of Bitcoin is 10 minutes). However, this usually never happens. This is because there are thousands of other transactions in the mempool waiting to be confirmed.
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Therefore, if the size of the mempool is very large, your transaction can remain unconfirmed for a while. Further, if a transaction remains in the mempool for too long, it will eventually be removed. This is because mempools have an expiry time of two weeks. Any transitions that remain in the mempool for more than two weeks will be cancelled, and the funds will return to your wallet.
What is mempool size?
Each transaction sent into the mempool is a data package no larger than a few kilobytes (kb). When we add these bytes, we arrive at the current size of the mempool. A larger size means that several transactions are waiting to be confirmed. It could also indicate increased network traffic, where more transactions are added to the mempool than confirmed. In this case, you will have to pay more transaction fees to confirm your transaction on priority.
While there is no maximum size as such, nodes can set a size limit to the mempool. This limit is usually 300MB. Once the mempool reaches this limit, nodes might assign a minimum transaction fee. Any transactions that do not meet this limit will be removed from the mempool. Further, the transactions will also be prioritized based on their transaction fee. This helps miners pick up prioritized transactions.
Seeing how mempool size can affect transaction times and fees, checking this factor before sending in a transaction is a smart move. Several websites allow you to check mempool sizes on the Bitcoin network. Some of the more popular options include BitcoinTicker.co, Jochen-hoenicke.de, Blockchain.com, etc.
Importance of mempools
Mempools are of advantage for both miners and users. They help miners pick up transactions based on priority, which can be helpful when there is a lot of traffic on the network. Miners can also download the current “transaction waiting list” to start confirming transactions. For users and the network, mempools provide resistance against DDoS attacks. These attacks occur when bad actors flood the network with minuscule transactions to create unmanageable congestion.
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FAQs
Bitcoin Mempool Summary
What is mempool in Bitcoin? ›
The mempool is the dynamic staging area in front of the blockchain that enables transaction ordering, transaction fee prioritization, and general block construction. The term itself —mempool— comes from Bitcoin.
What is the best way to explain Bitcoin mining? ›
Bitcoin mining is an energy-intensive process involving mining devices and software that compete to solve a cryptographic problem. The Bitcoin mining process also confirms transactions on the cryptocurrency's network. As an incentive to participate in the process, bitcoin is rewarded to those that win the competition.
What is the process of mining Bitcoin? ›
Mining is conducted by miners using hardware and software to generate a cryptographic number that is equal to or less than a number set by the Bitcoin network's difficulty algorithm. The first miner to find the solution to the problem receives bitcoins as a reward, and the process begins again.
Why are Bitcoin miners and Bitcoin mining important in the Bitcoin ecosystem? ›
Miners run important nodes in the Bitcoin network. Their nodes are the first ones to broadcast new blocks to the network to get them verified and added to each copy of the blockchain. Without miners in the network, no transactions would get added to the blockchain.
Why is mempool important? ›
This allows for easier confirmation of transactions. A transaction that is started by a user joins the network's mempool, which is made up of different nodes. Based on variables like transaction fees and block size, miners choose which transactions from the mempool to include in the blocks they mine.
What is the purpose of mempool? ›
Key Takeaways. A Bitcoin mempool is a storage space for unconfirmed transactions within each blockchain node on the network. Transactions with higher gas fees are generally executed faster due to miner incentives. Mempools vary in size and speed.
What is the most profitable way to mine Bitcoin? ›
ASIC Mining
ASIC mining, or Application-Specific Integrated Circuit mining, involves using specialized hardware designed specifically for mining cryptocurrencies. ASIC miners are highly efficient and powerful, making them the preferred choice for mining popular cryptocurrencies like Bitcoin.
How much does it cost to mine a Bitcoin? ›
$20K With 4.7c/Kwh. Mining a Bitcoin depends on your energy rate per Kwh, it costs $11,000K to mine a Bitcoin at 10 cents per Kwh and $5,170K to mine a Bitcoin at 4.7 cents per Kwh. Learn how and if mining right for you in 2024!
Is Bitcoin mining free? ›
Yes. Libertex provides free Bitcoin mining to its users via a virtual miner. There are no hidden charges or fees to start earning with our virtual Bitcoin miner. Miners may increase their mining speeds and, consequently, mining profit by upgrading their status in our customer loyalty programme.
How long does it take to mine one Bitcoin? It takes around 10 minutes to mine just one Bitcoin, though this is with ideal hardware and software, which isn't always affordable and only a few users can boast the luxury of. More commonly and reasonably, most users can mine a Bitcoin in 30 days.
Is Bitcoin mining legal? ›
Is bitcoin mining legal? According to TheStreet, reporting on a November 2021 Law Library of Congress report, bitcoin mining is banned in various countries, such as Bangladesh, China, Egypt, Iraq, Morocco, Nepal, Qatar, and more. However, it is legal in the US, and most countries, but not all US states allow the same.
How many years will it take to mine Bitcoin? ›
This leaves 0.78128% remaining. Due to the nature of the halving mechanism, it is believed that the very last Bitcoin will only be mined in 2140. In answering the question on how long it will take to mine the last Bitcoin, the answer is an estimated 119 years.
How do bitcoin miners get paid? ›
If a miner is able to successfully add a block to the blockchain, they will receive 3.125 bitcoins as a reward. The reward amount is cut in half roughly every four years, or every 210,000 blocks. As of April 2024, Bitcoin traded at around $63,000, making 3.125 bitcoins worth $196,875.
Who controls bitcoin mining? ›
Bitcoin is not controlled by any single group or person. Instead, it is governed by multiple stakeholders — including developers, miners, and users. Developers write the code that makes Bitcoin run; miners validate transactions; and users put the software to work by trading, transacting, holding, and more.
What happens to Bitcoin when it's all mined? ›
After all 21 million bitcoin are mined, which is estimated to occur around the year 2140, the network will no longer produce new bitcoin. The block subsidy will go to zero but miners will continue to receive transaction fees, which will make up an ever greater portion of the block reward.
How do I get my money out of mempool space? ›
mempool.space merely provides data about the Bitcoin network. It cannot help you with retrieving funds, wallet issues, etc. For any such requests, you need to get in touch with the entity that helped make the transaction (wallet software, exchange company, etc).
Can you remove a transaction from the mempool? ›
Bitcoin transactions can not be canceled. When you broadcast a transaction to the bitcoin network, it must be mined into a block on the blockchain to become confirmed. Until it's confirmed, it will wait with other unconfirmed transactions in the mempool.
How to withdraw Bitcoin from mempool? ›
How to withdraw Bitcoin from mempool? Once a transaction is in the Bitcoin mempool, it cannot be withdrawn but can sometimes be replaced using a method called Replace-By-Fee (RBF), where you essentially send the same transaction with a higher fee. Note that not all wallets support this feature.
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.
