What Is Bitcoin Mining?

Bitcoin mining is the process in which specialized computers called ASICs compete to produce new blocks, earning newly issued bitcoin and transaction fees in return. Miners bundle pending transactions into a block and make trillions of guesses per second to find a result that meets a difficult target set by the network. The first miner to hit it adds the block to the chain.

Mining isn’t just how new bitcoin is created. It confirms transactions and makes rewriting history prohibitively expensive, which is what secures the network. The method is called Proof of Work.

How does Bitcoin mining work?

1. A miner assembles a candidate block from the mempool, usually picking the transactions paying the highest fees.
2. It hashes the block header with SHA-256 over and over, changing the nonce each time.
3. When a hash comes in below the network’s target, the block is valid and gets broadcast.
4. Full nodes check it; if the transactions and reward follow the rules, they accept it.
5. The miner collects the block subsidy plus the fees from the transactions inside.

There’s no shortcut to the right answer, only guessing. More computing power raises your odds of finding a block but never guarantees it, while checking a winning answer takes a fraction of a second. Even a dominant miner can’t push through an invalid block, because nodes simply reject it.

What do miners earn? Block rewards and fees

Miner revenue has two parts: the new bitcoin the protocol allows per block (the block subsidy) and the fees from the block’s transactions. The subsidy is cut in half every 210,000 blocks, roughly every four years, in an event called the halving. It started at 50 BTC per block in 2009 and has been 3.125 BTC since the April 2024 halving.

As halvings continue and the subsidy shrinks, fees are expected to make up a growing share of miner income. Fee revenue swings sharply with network demand.

What are hashrate and mining difficulty?

Hashrate is the number of hash attempts per second. A single machine is measured in TH/s (trillions per second); the whole network’s estimated power is measured in EH/s (quintillions per second).

Mining difficulty sets how hard it is to find a valid result. Bitcoin adjusts it automatically every 2,016 blocks, about every two weeks: if blocks came faster than ten minutes on average, difficulty rises; if slower, it falls. That keeps block times near ten minutes no matter how many miners join.

The practical upshot: even if your machine stays the same, your share of rewards shrinks as total network hashrate grows.

What hardware do you need to mine bitcoin?

Today, Bitcoin mining is done almost entirely on ASICs built solely to compute SHA-256. Current models run at hundreds of TH/s and draw several kilowatts continuously, with plenty of noise and heat. Mining bitcoin on a graphics card, a CPU or a phone can’t compete economically.

When comparing machines, efficiency (joules per terahash, J/TH) matters more than raw speed. A faster machine that burns far more electricity can earn less. Apps promising “mine bitcoin on your phone” usually aren’t mining at all, and the points they show aren’t withdrawable BTC.

What is a mining pool?

A single machine’s chance of finding a block on its own is tiny. Mining pools combine the hashrate of thousands of miners and split the rewards according to each one’s contribution, turning rare large payouts into small, regular ones. Pools use payout schemes such as PPS, FPPS or PPLNS and typically charge a fee of a few percent, so compare the scheme as well as the headline daily rate.

Is Bitcoin mining profitable? An electricity cost example

Profitability comes down to the BTC price, network difficulty, your electricity rate and your machine’s efficiency. Here’s a simple electricity calculation with hypothetical numbers: a machine drawing 3 kW around the clock uses 3 × 24 = 72 kWh a day. At $0.10 per kWh, that’s $7.20 a day, or about $216 a month.

That leaves out cooling, ventilation, maintenance, pool fees and depreciation on the hardware. Revenue arrives in BTC, so its dollar value moves with the price, and rising difficulty means the same machine earns less bitcoin over time. Run your numbers across several price, difficulty and power-cost scenarios rather than projecting one good day forward. It’s why large mining firms build their sites next to cheap power.

Why does Bitcoin mining use so much energy?

Proof of Work’s security comes directly from the energy spent: an attacker trying to rewrite history would need more computing power, and therefore more energy, than all honest miners combined. That’s why Bitcoin’s electricity use sits at the center of both the criticism and the security argument. Because miners chase the cheapest power, they increasingly use stranded sources such as surplus hydro, wind, and natural gas that would otherwise be flared.

Is cloud mining legit?

With cloud mining you rent hashrate from a company for a fixed term, without owning or running the hardware. The space is full of scams. Promises of fixed, high returns don’t fit the reality of mining, where income depends on price, difficulty and fees. A growing balance on a dashboard doesn’t prove there’s withdrawable bitcoin, and a demand to “pay a fee before you can withdraw” is a classic red flag.

Mining or buying bitcoin?

Buying bitcoin carries price and custody risk. Mining adds hardware, energy, maintenance, downtime and operating risk on top, and machines lose efficiency and resale value within a few years. For most individuals, the simpler way to get bitcoin exposure is to buy bitcoin directly.

Sources

• Bitcoin: Mining and pools
• Bitcoin: Difficulty and block reward
• Bitcoin.org: Mining explanation