Mining is how new blocks are added to the blockchain and how new bitcoin is issued. It is less like digging and more like a global lottery that you enter by spending electricity.
The lottery
A miner collects transactions from the mempool, builds a candidate block, and hashes its header. The goal is a hash below a target number. Since hashes are unpredictable, the only way to win is to try again and again, changing a small field called the nonce each time. Modern ASIC machines do this trillions of times per second.
The prize
The winner broadcasts the block. Other nodes check it instantly — verifying is cheap, finding is expensive. If valid, the miner receives the block reward: newly created bitcoin plus all fees from the included transactions. Since the April 2024 halving the subsidy is 3.125 BTC per block.
Keeping time
Every 2,016 blocks (about two weeks) the network adjusts the difficulty so that blocks keep arriving roughly every 10 minutes, no matter how many miners join or leave.
Why it matters
Mining turns energy into security. To rewrite history, an attacker would need more computing power than all honest miners combined — the so-called 51% attack. At today's scale (over 1,000 EH/s, i.e. more than 1021 hashes per second, as of Oct 2026) that would likely require billions of dollars of hardware plus the electricity to run it.
The energy use is debated: critics see waste, supporters note miners seek the cheapest power, often stranded or renewable sources.