How Bitcoin Works
Where do new Bitcoins come from? Unlike traditional government-issued currency, which is printed and distributed by a central authority, Bitcoin operates on a decentralized system. There is no single entity in control.
Instead, individuals known as miners use specialized software to solve complex mathematical problems. Upon successfully solving these problems, they are rewarded with a specific number of bitcoins. This ingenious process not only creates new currency but also provides a powerful incentive for more people to participate in and support the network.
Why Bitcoin is a Secure Currency
Digital miners play a crucial role in maintaining the security and integrity of the Bitcoin network. By verifying and approving transactions, they help prevent fraud and double-spending. Mining is a fundamental component that ensures the entire process remains fair, transparent, and stable, thereby keeping the Bitcoin ecosystem secure for all users.
How Bitcoin Mining Functions
Bitcoin mining is the process of adding and verifying transaction records to the public ledger, known as the blockchain. This ledger is called a 'blockchain' because it is literally a chain of blocks, with each block containing a list of recent transactions.
Network nodes use the blockchain to distinguish legitimate Bitcoin transactions from illegitimate attempts to spend the same coins twice. This global, distributed consensus is what makes the system trustless and secure.
What is the Blockchain?
The blockchain is a public, immutable database that serves as the foundation for Bitcoin. Bitcoin mining is intentionally designed to be a computationally intensive and difficult process. This ensures that the rate at which new blocks are discovered by miners remains steady over time, approximately one every ten minutes.
For a block to be considered valid, it must contain a proof of work. This proof is verified by other Bitcoin nodes each time they receive a new block. Bitcoin utilizes a system called hashcash for its proof-of-work function.
The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus. Mining is also the mechanism through which new bitcoins are introduced into circulation. Miners are paid through transaction fees from users, as well as a "subsidy" of newly created coins.
This incentive serves two critical purposes: it distributes new coins in a decentralized manner, and it motivates people to contribute their computational power to secure the network. The term "mining" is used because the process resembles the extraction of a physical commodity like gold—it requires effort and slowly releases new currency at a predictable rate.
Comparing Bitcoin Mining Hardware
When selecting a mining device, two of the most critical factors are the price per hash (the computational power) and its electrical efficiency. Based on these metrics, some of the most effective Bitcoin miners available are:
AntMiner S7
- Hash Rate: 4.73 Th/s
- Power Efficiency: 0.25 W/Gh
- Weight: 8.8 pounds
- Profitability Score: 0.1645
AntMiner S9
- Hash Rate: 13.5 Th/s
- Power Efficiency: 0.098 W/Gh
- Weight: 8.1 pounds
- Profitability Score: 0.3603
Avalon6
- Hash Rate: 3.5 Th/s
- Power Efficiency: 0.29 W/Gh
- Weight: 9.5 pounds
- Profitability Score: 0.1232
👉 Compare the latest mining hardware efficiency
What is Proof of Work?
Proof of work (PoW) is a piece of data that is difficult (costly and time-consuming) to produce but very easy for others to verify once it's generated. It must satisfy a specific set of requirements defined by the network.
Producing a valid proof of work is a random process with a low probability of success, requiring a significant number of attempts, on average, before a miner finds a solution. Bitcoin's use of Hashcash as its proof-of-work algorithm is what makes the mining process so secure.
Understanding Bitcoin Mining Difficulty
The Computational Difficulty Problem
Mining a Bitcoin block is difficult because the SHA-256 hash of the block's header must be equal to or lower than a target value set by the network for the block to be accepted.
To simplify the concept: the hash of a block must start with a certain number of zeros. The probability of calculating a hash with many leading zeros is extremely low, requiring miners to make a vast number of attempts. To generate a new hash each time, a number called a nonce is incremented.
The Bitcoin Network Difficulty Metric
The Bitcoin network difficulty metric measures how hard it is to find a new block compared to the easiest it could ever be. This difficulty is recalculated every 2016 blocks. The system is designed so that these 2016 blocks should take approximately two weeks to mine, aiming for an average of one block every ten minutes.
As more miners join the network, the rate of block creation increases. In response, the network automatically increases the mining difficulty to compensate, pushing the block creation rate back down to the target time. Any blocks released by miners that do not meet the required difficulty target are simply rejected by everyone on the network and are worthless.
The Block Reward
When a miner successfully discovers a new block, they are entitled to award themselves a certain number of bitcoins, an amount agreed upon by all network participants. This is known as the block reward. Initially set at 50 bitcoins, this reward is halved approximately every four years (or every 210,000 blocks) in an event known as the "halving." This controlled supply mechanism is a key feature of Bitcoin's economic model.
In addition to the block reward, the miner also collects all the transaction fees from the transactions included in that block. These fees serve as an incentive for the miner to prioritize and include those transactions in their block.
In the future, as the block reward continues to halve and eventually approaches zero, transaction fees are expected to constitute a much more significant percentage of a miner's total income, ensuring the long-term security of the network.
Frequently Asked Questions
What is the main purpose of Bitcoin mining?
Mining serves two primary purposes: it secures the network by verifying transactions and preventing double-spending, and it is the mechanism through which new bitcoins are created and introduced into circulation in a decentralized way.
Can I mine Bitcoin with my personal computer?
No, mining Bitcoin with a standard CPU or GPU has not been profitable for many years. The network difficulty is now so high that it requires specialized hardware called ASICs (Application-Specific Integrated Circuits) to compete effectively.
How do miners verify transactions?
Miners collect pending transactions from the network and compile them into a candidate block. They then repeatedly hash the block's header, slightly altering it each time, until they find a hash that meets the network's current difficulty target. This valid proof of work is broadcast to the network for other nodes to verify.
Is Bitcoin mining profitable?
Profitability depends on several variables, including the cost of electricity, the efficiency and cost of your mining hardware, and the current price of Bitcoin. It requires careful calculation of operational expenses versus potential rewards. 👉 Calculate your potential mining profitability
What happens when all 21 million bitcoins are mined?
Once the maximum supply of 21 million bitcoins has been mined, miners will no longer receive block rewards. Their income will rely solely on transaction fees paid by users. The system is designed to incentivize miners to continue securing the network through these fees.
What is a mining pool and should I join one?
A mining pool is a group of miners who combine their computational resources to increase their chances of finding a block. Rewards are then shared among participants based on the amount of work they contributed. For individual miners with limited hardware, joining a pool provides a more steady and predictable stream of income than solo mining.