Mining is the process of competing to add blocks to a proof of work blockchain. Miners run specialized hardware performing trillions of hash calculations per second, searching for a number that makes the block hash fall below a target. The winner receives newly issued coins plus transaction fees. Bitcoin mining is now an industrial business and is not viable on home hardware.
The puzzle
A miner assembles candidate transactions into a block, adds a number called a nonce, and hashes the whole thing. If the resulting hash starts with enough zeros, the block is valid. If not, change the nonce and try again.
There is no clever approach. The only method is guessing, at enormous speed. Modern Bitcoin mining hardware performs hundreds of trillions of guesses per second, and the whole network performs vastly more.
Difficulty adjustment
Bitcoin targets ten minute blocks. As more hardware joins, blocks would arrive faster, so every 2016 blocks the network recalculates difficulty to bring the pace back to target.
This is why more mining does not produce more bitcoin. Issuance is fixed by schedule, and additional hardware only makes each individual miner's share smaller.
The economics
| Input | What determines it |
|---|---|
| Revenue | Block reward plus fees, multiplied by your share of total hash rate |
| Electricity | The dominant cost. Viability depends almost entirely on cost per kilowatt hour |
| Hardware | Specialized machines that depreciate quickly as newer ones arrive |
| Cooling and hosting | Nontrivial. These machines produce serious heat and noise |
| Difficulty | Rises as competitors join, reducing your share continuously |
Mining pools
A solo miner with a small share of hash rate might find a block once every several decades. Pools solve this by combining hash rate and splitting rewards proportionally.
The result is steady income instead of a lottery. It also concentrates block production among a small number of pool operators, which is the most substantive decentralization criticism of Bitcoin today.
The energy question
Bitcoin consumes electricity on the scale of a mid sized country. That is real, it is intentional, and it is what backs the security.
The nuances worth knowing: miners chase the cheapest power, which is often energy nobody else can use, such as flared gas or curtailed renewables in remote locations. Miners can also switch off within seconds, which makes them a uniquely flexible grid load. And electricity use is not carbon emissions, which depend on the source mix.
None of that resolves the debate. It does mean the informed version of the argument is about what the energy buys, not about the number of terawatt hours.
Other mineable chains
Bitcoin is not the only proof of work chain. Litecoin uses a different algorithm, and Monero uses RandomX, which is deliberately designed to run well on ordinary CPUs specifically to keep mining accessible to individuals.
Monero is one of the few chains where home mining still means something, and even there the returns are modest.
Common questions
Can I mine Bitcoin at home?
Technically yes, economically no. Home electricity rates and consumer hardware cannot compete with industrial operations on cheap power contracts. Expect to spend more on electricity than you earn.
What happens when all bitcoin is mined?
Around 2140 the block reward reaches zero and miners are paid entirely from transaction fees. Whether fees alone can fund adequate security is a genuine open question, debated seriously and not urgently.
Is mining bad for the environment?
It consumes a lot of energy, which is not in dispute. The impact depends on the source mix, and a meaningful share uses energy that would otherwise be wasted. Reasonable people weigh this differently.
What is a mining pool?
A group combining hash rate to find blocks more regularly and split rewards proportionally. Almost all mining happens through pools, which is also the main concentration concern.
Where to go next
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