Mining Basics

What Is Bitcoin Mining?

Bitcoin mining is the process of using specialized computers to validate transactions and add new blocks to the Bitcoin blockchain. Miners compete to solve a computational puzzle, and the first miner to find a valid solution gets to add the next block of transactions and earn the associated reward.

Think of it as a global lottery that runs every ten minutes. Thousands of miners around the world are simultaneously guessing numbers, trying to find one that produces a specific result when put through a cryptographic hash function. The winner gets paid in newly created bitcoin plus the transaction fees from every transaction included in that block.

But mining is not just about earning bitcoin. It serves three critical functions for the network:

• Transaction validation: Miners verify that every transaction follows Bitcoin's rules. No double spending, no creating coins from nothing, no spending coins you do not own.
• New coin issuance: Mining is the only way new bitcoin enters circulation. The supply schedule is hardcoded and predictable. No central bank decides to print more.
• Network security: The computational work required to mine a block makes it prohibitively expensive to alter the transaction history. The more hashrate on the network, the more secure it becomes.

Every ten minutes, on average, a new block is added to the chain. Every block is permanently linked to the one before it through cryptography. To change any past transaction, an attacker would need to redo the work for that block and every block that came after it, which becomes computationally impossible as more blocks are added. What is Bitcoin?

How Proof of Work Actually Works

Proof of work (PoW) is the consensus mechanism that makes Bitcoin trustless. Instead of relying on a trusted third party to verify transactions, Bitcoin relies on physics and mathematics. Here is how the process works, step by step:

The genius of proof of work is that it makes creating a valid block extremely expensive but verifying it nearly free. Any node on the network can check a block's validity in milliseconds, but finding that valid block requires trillions of computations.

Why SHA-256?

Bitcoin uses the SHA-256 hash function (Secure Hash Algorithm, 256-bit). This function takes any input and produces a fixed 256-bit output that appears random. Even a tiny change to the input produces a completely different hash. This property, called the avalanche effect, means there is no way to predict what nonce will produce a valid hash. You can only guess and check.

SHA-256 has been extensively analyzed by cryptographers worldwide since its publication by the NSA in 2001. No practical vulnerability has ever been found. It is the same hash function used by banks, governments, and military systems globally.

Hashrate Explained

Hashrate is the speed at which a miner can perform hash computations. It is measured in hashes per second (H/s), and Bitcoin mining typically uses terahashes per second (TH/s) or exahashes per second (EH/s) for network-level measurements.

Your Hashrate vs. the Network

Your probability of finding the next block is directly proportional to your hashrate relative to the total network hashrate. If the network runs at 950 EH/s and your miner does 318 TH/s, your chance of finding any given block is roughly 0.00000003%. That is why solo mining with a single device is essentially a lottery, and why most miners join pools. Pool Tutorial

Efficiency: Joules per Terahash

Raw hashrate alone does not determine profitability. What matters is efficiency: how much energy your miner uses per unit of hashrate. This is measured in joules per terahash (J/TH). The Antminer S23 doing 318 TH/s at 3,498 watts achieves 11 J/TH. The older S19k Pro doing 120 TH/s at 2,760 watts achieves 23 J/TH. The S23 is roughly twice as efficient, meaning it earns more per dollar of electricity spent. Hardware Comparison

Block Rewards and the Halving

The miner who finds a valid block earns two types of revenue: the block subsidy (newly created bitcoin) and the transaction fees from all transactions included in that block.

Every 210,000 blocks (approximately every four years), the block subsidy is cut in half. This is the halving. It is hardcoded into Bitcoin's protocol and cannot be changed by anyone. The halving ensures that Bitcoin's total supply never exceeds 21 million coins and that issuance follows a predictable, disinflationary schedule.

As the block subsidy shrinks over time, transaction fees become a larger percentage of miner revenue. During periods of high network activity (like ordinals inscriptions or major market moves), transaction fees can temporarily exceed the block subsidy. This transition from subsidy-dominant to fee-dominant revenue is a critical economic evolution for mining. Halving Countdown

The Difficulty Adjustment

Bitcoin's difficulty adjustment is one of the most elegant pieces of engineering in the protocol. Every 2,016 blocks (about two weeks), the network automatically recalibrates how hard it is to mine a block, targeting an average block time of ten minutes.

If the previous 2,016 blocks were mined faster than expected (because more hashrate joined the network), difficulty increases. If blocks were slower (because miners left), difficulty decreases. This ensures that block production remains consistent regardless of how many miners are operating.

The difficulty adjustment is what makes Bitcoin's supply schedule reliable. No matter how much mining hardware enters or leaves the network, blocks keep coming every ten minutes on average.

This mechanism also creates a self-balancing economic system. When Bitcoin's price rises, mining becomes more profitable, attracting more hashrate. More hashrate triggers a difficulty increase, which raises the cost of mining. When the price falls, some miners shut down, difficulty drops, and the remaining miners become more profitable. It is a continuous equilibrium. Live Network Stats

Why Mining Matters Beyond Profit

The financial calculation is important, but it misses the bigger picture. Mining serves functions that go beyond the miner's individual return on investment.

Decentralization

Every home miner who runs their own hardware contributes to geographic distribution of hashrate. When mining is concentrated in a few large data centers in a few countries, it creates points of failure. Governments can raid data centers, impose regulations, or cut power. A million home miners spread across the world are nearly impossible to shut down collectively.

Censorship Resistance

Miners choose which transactions to include in blocks. If all mining is controlled by a few entities that can be pressured by governments, those entities can be forced to censor specific transactions. A diverse set of independent miners makes transaction censorship practically impossible.

Non-KYC Bitcoin

Mining is one of the few remaining ways to acquire Bitcoin without providing personal identification to a third party. Freshly mined coins have no transaction history and cannot be linked to previous owners. For individuals who value financial privacy, mining provides something that exchanges cannot.

Protocol Education

Running a miner teaches you how Bitcoin works at a level that no article, book, or video can match. You will understand block propagation, fee markets, pool dynamics, difficulty adjustments, and energy economics through direct experience. Many of Bitcoin's most knowledgeable advocates started as small home miners.