Topic · How blockchains work
What is hash rate?
- Quick fact 1
Bitcoin miners repeatedly hash block headers looking for one below the target.
Source: Bitcoin developer guide: Mining
- Quick fact 2
Bitcoin adjusts its difficulty so that blocks keep arriving about every 10 minutes on average.
- Quick fact 3
Proof of work makes rewriting history expensive because an attacker would need to redo the work.
The short lesson
Hash rate is speed: how many hash guesses per second. A single mining machine has a hash rate. The whole bitcoin network has a total hash rate, the sum of every miner.
Mining is a guessing game. Miners hash a block header with a different nonce again and again until one result falls below the target. More hash rate means more guesses per second.
Why the network’s hash rate matters
- Security. To rewrite recent history, an attacker would need more hashing power than the honest network. The bigger the total, the harder and costlier that is. See 51% attack.
- Difficulty. If hash rate rises, blocks would come faster, so bitcoin raises the difficulty about every two weeks (every 2,016 blocks). If it falls, difficulty drops. Blocks stay near 10 minutes.
What it does not tell you
Hash rate is a measure of security work, not a price signal. Treat headlines that turn hash rate into buy or sell predictions with care.
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Related terms
Go deeper in Lesson 4: The shared list everyone can check
More in How blockchains work
Common questions
What units is hash rate in?
Hashes per second, often in large units like terahashes (TH/s) or exahashes (EH/s).
Does Ethereum have hash rate?
Not since 2022. Ethereum moved to proof of stake, which does not use mining.
If hash rate drops, is bitcoin unsafe?
Difficulty adjusts to keep blocks steady. Security depends on the total work, so big drops are watched closely.
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Reviewed and sources
Written and reviewed by Joshua Baskin, founder. Last reviewed . How we check facts · Report an error
Education only. Not investment, tax or legal advice. We do not pick coins.