Mining
How miners compete to add blocks, why it costs energy and how new bitcoin is issued.
What is Bitcoin mining?
Bitcoin mining is a worldwide race to find a rare hash. The winner adds the next block and earns new bitcoin plus fees. Try our mining simulator.
Proof of work
Proof of work means a block's hash is so rare that finding it took huge effort, yet anyone can check it instantly. See how it secures Bitcoin.
The nonce
The nonce is a 4-byte number in the block header that miners change on every attempt. Learn why it runs out so fast and what miners change next.
Target and difficulty
The target is the number a block hash must be below; difficulty says how much harder that is than the first target. Learn how both are calculated.
Difficulty adjustment
Every 2,016 blocks, about two weeks, Bitcoin resets mining difficulty so blocks average 10 minutes again. Learn the formula and the limits.
The block reward
The block reward is what a miner earns for a block: the subsidy (new bitcoin) plus all transaction fees. See today's reward and how it is changing.
The Bitcoin halving
Every 210,000 blocks the new bitcoin per block is cut in half. Halvings happened in 2012, 2016, 2020 and 2024; the next is due around 2028.
Mining pools
A mining pool combines many miners' hash power and shares the rewards, giving each small regular payouts instead of rare jackpots. Learn how pools work.
ASIC miners
ASIC miners are chips built only to compute SHA-256 as fast and efficiently as possible. Learn how they replaced CPUs and GPUs and what specs matter.
Hashrate
Hashrate is how many hashes per second the Bitcoin network performs. It can't be measured directly; learn how it's estimated and why it matters.
The 51% attack
An attacker with most of the hash power could rewrite recent blocks and double spend their own coins, but could not steal coins or change Bitcoin's rules.