Mining is how Bitcoin achieves consensus without trusting anyone. Computers compete to solve a cryptographic puzzle; the winner writes the next block and collects the block reward. The puzzle difficulty adjusts every 2,016 blocks so blocks arrive roughly every 10 minutes no matter how much global hash power joins or leaves.
READING TIME: ~8 MIN
Mining is a lottery with cryptography. Specialized computers (ASICs) burn electricity to guess numbers that produce a valid block hash. The first to find one wins the right to write the next block and collect the reward, currently 3.125 BTC plus transaction fees. The puzzle retargets every two weeks so the network produces one block roughly every ten minutes, whether ten thousand miners are competing or ten million. Proof of work is what makes the ledger honest. You cannot fake it. You have to spend real energy.
Think of mining as a raffle that runs continuously. Each time a miner computes a hash, it is buying one ticket. The more hashes per second a miner can compute, the more tickets it holds. The network draws a winning ticket roughly every ten minutes.
If you control one percent of the global hash rate, you will find roughly one percent of the blocks over time. Expected time between your blocks is the block interval (ten minutes) divided by your share. At one percent, that is about every sixteen hours. At 0.001 percent, it is about every two years on average, with enormous variance.
There is no partial credit. Miners either find the block or they do not. This is why small miners join pools that split rewards proportionally to contributed work, or solo-mine and accept long odds of a large payout.
Every block header is fed through SHA-256 twice. The output is a 256-bit number. For the block to be valid, that number must be lower than a target value set by the protocol. The target looks like a long string of leading zeros in hex.
Miners cannot choose the output of SHA-256. They can only change one small field in the header (the nonce, plus a few other tweaks) and try again. Hash, check, increment, hash, check, increment. A modern ASIC can do this hundreds of trillions of times per second.
A "valid block hash" is just a SHA-256 output that, read as a number, is below the current target. Nothing more. The cryptographic work is the brute-force search for an input that produces such an output. The protocol then rewards whoever found one first.
Every 2,016 blocks (roughly every two weeks at ten-minute intervals) the network adjusts the target based on how fast the previous 2,016 blocks were mined. If they came in faster than two weeks, the target tightens (difficulty goes up). If they came in slower, the target loosens (difficulty goes down).
This is the mechanism that keeps block time at roughly ten minutes regardless of how much global hash rate joins or leaves. When China banned mining in mid-2021, global hash rate fell roughly 50 percent in weeks [VERIFY]. Blocks slowed to fifteen to twenty minutes. At the next adjustment, difficulty dropped, and block time returned to ten minutes on a smaller network. Six months later, when miners had relocated and rebuilt capacity, hash rate was at new all-time highs and difficulty had climbed to match.
Each block pays its miner two things: a newly-minted "coinbase" reward and the fees attached to the transactions included in the block. The coinbase started at 50 BTC per block in 2009 and halves every 210,000 blocks (roughly every four years).
After the April 2024 halving the reward is 3.125 BTC per block. At a Bitcoin price around $80,000 [VERIFY], that is roughly $250,000 of new issuance per block plus a few thousand dollars in fees, paid every ten minutes to whichever miner wins. See The Bitcoin Halving for the full schedule.
Network hash rate is the total number of SHA-256 hashes the entire network computes per second, summed across every machine. In early 2026 it is running at roughly 700 to 900 EH/s [VERIFY mempool.space or hashrateindex.com]. That is 700-900 exahashes per second, which is 700-900 quintillion hashes every second.
To rewrite a confirmed Bitcoin transaction, an attacker must recompute all the proof of work that has been layered on top of it, faster than the honest network adds new work. This is the 51 percent attack. At 2026 hash rates, it is economically absurd. An attacker would need to build or rent hardware worth tens of billions of dollars, secure enough electricity to run it at nation-scale power draw, operate undetected, and still burn most of the value of the Bitcoin they were trying to steal in the process of stealing it.
That is the actual security model. It is not legal or institutional. It is thermodynamic. Reversing history requires spending more energy than the history was written with.
A personal note. I run a Bitaxe Gamma Duo at home, solo-mining through solo.ckpool.org. The odds of finding a block at hobbyist hash rates are vanishingly small. The point is not profit. It is participation in the network, and watching the machine do the actual work that keeps Bitcoin honest. If you want the full walk-through see How Bitcoin Mining Works.
Fiatisfake editorial noteLast updated 2026-04-14. Not financial advice. Do your own research.