How Does Bitcoin Mining Work?

Bitcoin has no central bank and no company that confirms payments. Instead, a worldwide network of miners does that job, competing to add the next block of transactions to the blockchain. In return, they receive newly created bitcoin and the fees users pay. This process keeps the network secure, controls the release of new coins and is one of the most energy-intensive activities in digital finance. Here is how it works.

What Bitcoin mining actually does

Mining serves three purposes at once:

1. It confirms transactions. New transactions wait in a queue called the mempool. Miners select transactions, usually those paying the highest fees, and bundle them into a block.
2. It secures the history. Each block contains a reference to the previous one. Changing an old transaction would require redoing all the work for that block and every block after it, which is practically impossible.
3. It issues new bitcoin. The only way new bitcoin enters circulation is through the block reward paid to the successful miner.

Proof of work, step by step

1. Build a candidate block. A miner collects transactions and adds a special transaction that pays the block reward to itself.
2. Hash the block header. The miner runs the block's header, a summary of about 80 bytes, through the SHA-256 hash function twice. The result is a seemingly random 64-character number.
3. Compare with the target. The block is only valid if the hash is below a target value set by the network. Because hash outputs are unpredictable, the only way to find a valid one is trial and error.
4. Change a number and try again. The miner changes a field called the nonce (and other variable data) and hashes again, trillions of times per second.
5. Broadcast the winner. The first miner to find a valid hash broadcasts the block. Other nodes check it instantly; if it is valid, they add it to their copy of the blockchain and the race for the next block begins.

Finding a valid hash is extremely hard, but verifying it takes a fraction of a second. That asymmetry is what makes proof of work secure: cheating is expensive, while checking is cheap.

Mining difficulty and the 10-minute rhythm

Bitcoin aims for one block about every 10 minutes. If more miners join, blocks would come faster; if miners leave, they would slow down. To keep the pace stable, the network recalculates the difficulty every 2,016 blocks, roughly every two weeks, based on how long the previous 2,016 blocks took.

The total computing power of all miners is called the hashrate. It crossed 1 zettahash per second (1,000 exahashes, or one sextillion hashes per second) for the first time in 2025 and peaked at around 1,150 EH/s in October 2025. In 2026, it dipped back below that level at times. In February 2026, difficulty jumped by about 15% in a single adjustment, the largest increase since 2021, while later adjustments mostly moved lower as miners came under pressure.

What miners earn: block reward and fees

A miner's income per block has two parts:

• The block subsidy: 3.125 BTC since the April 2024 halving. It is cut in half every 210,000 blocks; the next halving, expected around April 2028, will reduce it to 1.5625 BTC.
• Transaction fees: paid by users to get their transactions included. Fees vary with network demand and are expected to become more important as the subsidy shrinks.

Newly mined coins can only be spent after 100 further blocks have been added, a safety rule in case two competing blocks are found at the same time.

Miners often measure revenue as hashprice, the expected income per unit of computing power per day. It fell from around $70 per petahash per second per day in October 2025 to about $24 in February 2026, as the bitcoin price dropped while difficulty kept rising. That squeeze pushed less efficient miners out of the market.

Mining hardware: from laptops to ASICs

Modern ASIC miners do nothing but compute SHA-256 hashes, at hundreds of terahashes per second. Their key metric is energy efficiency, measured in joules per terahash (J/TH). The newest machines operate below 20 J/TH, and some are considerably more efficient. Older, less efficient machines become unprofitable quickly after a halving or a price decline.

Mining pools: sharing the work

With the network's enormous hashrate, a single miner might wait years to find a block. That is why almost all miners join mining pools, which combine the computing power of thousands of participants and share rewards in proportion to the work contributed, minus a pool fee. A handful of large pools find most blocks. For example, the pool Foundry USA mined the block that pushed Bitcoin's supply past 20 million coins in March 2026.

Pool concentration is a recurring concern, because pool operators decide which transactions go into blocks. However, individual miners can switch pools quickly, which limits a pool's power.

Energy use and the environment

Proof of work consumes large amounts of electricity; by many estimates, the Bitcoin network uses as much power as a mid-sized country. Critics see this as wasteful. Supporters argue that the energy is what makes the network secure, that miners increasingly use stranded or surplus energy, such as flared gas or excess renewable power, and that miners can switch off quickly to help stabilize electricity grids during demand peaks.

In 2025 and 2026, a new trend emerged: artificial intelligence data centers compete with miners for the same power connections, sites and capital. Several mining companies have shifted part of their capacity to AI and high-performance computing. For a comparison with Ethereum's far less energy-intensive proof-of-stake system, see Bitcoin vs Ethereum.

Can you still mine Bitcoin at home?

Technically yes, but it rarely pays off. Profitability depends on four factors: the bitcoin price, the network difficulty, your hardware's efficiency and, above all, your electricity price.

Home miners also have to deal with noise (ASICs are as loud as a vacuum cleaner), heat and the risk that the next halving or a drop in price makes their equipment unprofitable. For most people who simply want to own bitcoin, buying it is cheaper and far simpler.

Mining and security: what is a 51% attack?

If a single entity controlled more than half of the network's hashrate, it could in theory prevent certain transactions from being confirmed or reverse its own recent transactions (a "double spend"). It could not steal coins from other people's wallets or create bitcoin out of thin air. Given the size of today's network, such an attack would require billions of dollars in hardware and energy, and it would likely destroy the value of the very coins the attacker earns.

How mining income is taxed

In the US and many other countries, mined bitcoin is taxable income at its market value on the day you receive it. When you later sell it, any change in value is a capital gain or loss. Professional miners may also owe self-employment or business taxes. Read Bitcoin taxes explained for details.

The future of Bitcoin mining

About 20.1 million of the 21 million bitcoin have already been mined. Because the reward keeps halving, the remaining coins will be released ever more slowly, with the final fractions expected around the year 2140. Over time, miners will depend more on transaction fees. Whether fees will be high enough to fund strong security in the long run is one of the most debated questions about Bitcoin's future.

Frequently asked questions

How long does it take to mine one bitcoin?

The network as a whole produces 3.125 BTC about every 10 minutes. For an individual miner, it depends on their share of the total hashrate; with a single home machine, it would take many years on average.

Is Bitcoin mining legal?

In most countries, including the US, UK and EU members, yes. Some countries restrict or ban it, often because of energy concerns.

What happens when all bitcoin are mined?

Miners will be paid only through transaction fees. That point is expected around 2140.

Why does mining use so much energy?

Because security comes from making it costly to produce blocks. The more computing power competes, the more expensive it becomes to attack the network.

Can I mine Bitcoin on my phone or laptop?

Not in any meaningful way. Apps that claim to let you mine bitcoin on a phone are typically games, cloud-mining offers or scams.