Hash rate: measuring blockchain mining power

What Hash Rate Actually Measures

Hash rate is the total number of hash computations performed per second by all miners on a Proof-of-Work network. Each hash is an attempt to solve the cryptographic puzzle that produces the next valid block. The higher the hash rate, the more guesses the network is making every second, and the more secure the chain becomes against attackers trying to rewrite history.

The numbers are astronomical. Bitcoin's hash rate is typically measured in exahashes per second (EH/s)—quintillions of operations every second. To put this in perspective, an attacker hoping to control more than half of the network would need to assemble computing power rivaling the entire honest mining industry, which today costs billions in hardware and electricity.

Hash rate rises and falls with profitability. When the Bitcoin price climbs, more miners turn on machines and new fleets come online, pushing the rate up. When the price drops or electricity becomes expensive, the least efficient miners shut down. The protocol adjusts mining difficulty roughly every two weeks to keep block times near ten minutes, regardless of how much total computing power is online.