GUIDE: How does Bitcoin mining work?

What exactly a miner does

A miner is a specialized computer that collects pending transactions, groups them into a block, and searches for a number (the nonce) which, combined with the block's content, produces a cryptographic hash below a very demanding target.

There are no shortcuts: the only way to find that number is to try trillions of combinations per second. It's like rolling gigantic dice until you get a specific outcome. When a miner succeeds, they broadcast the block, and the rest of the network verifies the solution is correct in milliseconds. Finding it is extremely difficult; verifying it is instant.

The winning miner receives two types of income: the block reward, consisting of new bitcoins, and the transaction fees paid for the transactions included in that block.

Difficulty and ten-minute pace

Bitcoin adjusts the difficulty of the problem every 2,016 blocks, approximately every two weeks. If more miners join and blocks are found too quickly, the difficulty increases. If equipment is turned off, it decreases. The goal is to maintain one block every ten minutes on average, no matter what.

This automatic adjustment is one of the most elegant pieces of Bitcoin's design: it makes the issuance of new coins predictable for decades, regardless of how much computing power is connected.

The halving and the 21 million limit

Every 210,000 blocks, approximately every four years, the block reward is cut in half. It started at 50 bitcoins in 2009, then dropped to 25, then to 12.5, then to 6.25, and in 2024 it fell to 3.125. This mechanism, called halving, will ensure that there will never be more than 21 million bitcoins.

As the reward decreases, transaction fees gain more weight in miners' income. In the long term, the security of the network will depend mostly on them.

Energy, hardware, and profitability

Professional mining is done with ASIC equipment, designed exclusively for calculating hashes. A normal computer or graphics card has no chance of competing: the difference in efficiency is several orders of magnitude.

The main cost is electricity. That's why large farms are set up where energy is cheap and abundant: hydroelectric in Scandinavia and Canada, geothermal in Iceland, associated gas that would otherwise be flared, or solar farms with surpluses. More and more operators participate in demand response programs, shutting down equipment when the electrical grid is stressed.

Is it worth mining at home? Unless you have very cheap electricity and can manage the noise and heat, almost never. For most people, buying Bitcoin directly is more efficient and much simpler than trying to produce it.

Cloud mining, pools, and what to look for before participating

When someone decides to participate in mining without setting up a farm, two paths emerge: joining a pool with their own equipment or contracting cloud mining. A pool is a group of miners who combine their computing power and distribute rewards proportionally to the work contributed. Solo mining with a single piece of equipment is almost a lottery today: you could go years without finding a block. In a pool, however, earnings are small but constant. Before choosing one, it's advisable to check the fee it charges, the distribution method, the minimum withdrawal amount, and what percentage of the network it controls, because excessive concentration in a few pools weakens the decentralization that gives value to the network.

Cloud mining is much more slippery ground. The promise is simple: you pay for computing power that someone else operates for you, and you receive a share of the rewards. The problem is an abundance of contracts with unrealistic figures, maintenance fees that eat up profits, and companies that have never proven to have a single piece of equipment running. If you're still interested, demand transparency about the location of data centers, the hardware model used, the electricity price applied, and the possibility of terminating the contract. A contract that guarantees a fixed profitability is, by definition, a red flag: mining revenues depend on the price of Bitcoin and network difficulty, and neither variable can be guaranteed.

To calculate if an operation makes sense, four pieces of data are needed: the equipment's electricity consumption in watts, the price you pay per kilowatt-hour, the equipment's computing power, and the current average reward per unit of power. This yields the cost of producing one Bitcoin. If that cost is above the market price, you're losing money every day the equipment remains on. To this calculation, you must add the depreciation of hardware, which ages quickly, and often-forgotten expenses: ventilation, soundproofing, maintenance, and physical space.

Finally, there's the environmental dimension, which generates a lot of debate. The network's energy consumption is high, but a growing portion comes from surplus renewables or gas that would otherwise be flared. Miners are flexible consumers: they can shut down in seconds when the electrical grid needs it, something few industries can offer. For most readers, however, the practical conclusion remains the same: buying Bitcoin periodically on a regulated platform is simpler, cheaper, and significantly less risky than trying to produce it.