Bitcoin mining is the process by which specialised computers compete to add the next block of transactions to the ledger, earning newly issued bitcoin and fees in return. That competition is what secures the network: to reverse a settled payment, an attacker would need to outspend all honest miners combined. For a treasury holding Bitcoin, mining matters not as an activity to join but as the mechanism that makes its holdings final.
We explain mining as education only. The Bitcoin World does not offer mining services.
What Bitcoin mining actually does
Mining has three functions:
- Ordering. Miners select pending transactions and put them in a sequence, settling which of two conflicting payments came first.
- Securing. Each block requires a large amount of computing work, which makes rewriting history expensive.
- Issuing. New bitcoin enters circulation as the block subsidy paid to the successful miner, on a fixed schedule.
Miners do not decide the rules. A block that breaks them, for example by paying the miner too much, is rejected by nodes regardless of the work behind it. See what is a Bitcoin node.
How a block is mined
A miner assembles a candidate block: a header that references the previous block, a summary of chosen transactions, and a first transaction that pays the miner.
The miner then repeatedly changes a small field in the header and computes its fingerprint (hash). The goal is a fingerprint below a target number set by the network. There is no shortcut; the only way is trial and error, billions of times per second, using dedicated chips called ASICs.
When a miner finds a valid block, it broadcasts it. Nodes check it, and other miners start building on top of it. The winning miner collects:
- The block subsidy, currently 3.125 BTC after the April 2024 halving.
- All transaction fees in the block.
Most miners join pools that combine computing power and share rewards, which smooths their income.
Pools coordinate work but do not own the hardware. Individual miners can, and occasionally do, switch pools quickly if a pool operator behaves badly. That ability to move is one of the checks that stops any single pool turning a large share of computing power into lasting control.
Mining is also a competitive industry with thin margins at times. Miners' main costs are hardware and electricity, and their revenue is set in bitcoin. When the price falls or the subsidy halves, the least efficient machines switch off, the difficulty adjusts, and the network carries on.
The difficulty adjustment
The network aims for one block roughly every ten minutes. Every 2,016 blocks, about two weeks, it compares how long those blocks actually took and adjusts the target.
- If blocks came too fast, mining becomes harder.
- If they came too slowly, it becomes easier.
This self-correction is central to Bitcoin's predictability. When large amounts of mining capacity went offline in 2021, after China banned mining, blocks slowed briefly and then the difficulty fell and the ten-minute rhythm returned. Issuance stayed on schedule.
Why mining makes settled transactions final
To reverse a confirmed transaction, an attacker would need to produce an alternative chain from before that transaction, and outpace the honest network until their chain is longer. This is often called a 51% attack.
The cost of such an attack has several parts:
- Hardware. Acquiring or redirecting more computing power than the rest of the network, which means a vast fleet of specialised equipment that is not readily available to buy.
- Energy. Running it for as long as the attack lasts.
- Opportunity cost. Honest mining would have earned the rewards instead.
- Self-harm. A visible attack would likely damage the value of the attacker's own equipment and any bitcoin it holds.
Even a successful attacker could only reorder or reverse its own recent transactions. It could not forge signatures, take other people's coins or change the supply rules.
| Threat | Can a majority miner do it? |
|---|---|
| Reverse its own recent payment | Yes, at great cost |
| Block specific transactions temporarily | Yes, while it holds a majority |
| Steal bitcoin from other addresses | No |
| Create bitcoin beyond the schedule | No, nodes reject it |
The security budget over time
Miner revenue is the network's security budget. Today it comes mostly from the block subsidy, which halves every 210,000 blocks. Over the coming decades, fees must make up a larger share for miners to keep investing at today's scale.
Whether fee income will be sufficient is a genuine, open debate. It depends on future demand for block space, the bitcoin price and mining costs. A treasury does not need to resolve it, but a board paper should acknowledge it as a long-horizon consideration. See the Bitcoin halving explained.
In your board materials, separate what is mechanical and predictable (issuance, difficulty adjustment) from what is uncertain (future fee income and price), and label each clearly.
What this means for a corporate holder
- Confirmation policy. Waiting for several blocks before treating a large receipt as final is a direct response to how mining security works.
- Hash rate as context. Total computing power is a public indicator of the cost to attack. Sharp falls are worth noting in risk reporting.
- Energy questions. Investors may ask about mining's energy use. Prepare a factual answer; we cover the economics in proof of work explained.
How The Bitcoin World helps
We help finance teams translate network mechanics into treasury policy, including confirmation thresholds, risk reporting and board explanations. We do not offer mining. Execution and custody are carried out by licensed third-party institutions. See our board advisory work.