Hash rate refers to the total number of hash computations a blockchain network or individual mining device can perform per second. It is the primary metric for measuring the computational power dedicated to securing a Proof of Work blockchain like Bitcoin.
Hash rate is expressed in units such as:
- KH/s — kilohashes per second (thousands)
- MH/s — megahashes per second (millions)
- GH/s — gigahashes per second (billions)
- TH/s — terahashes per second (trillions)
- EH/s — exahashes per second (quintillions)
Bitcoin's network hash rate currently operates in the hundreds of EH/s range, reflecting the enormous computational resources committed by miners worldwide.
A higher hash rate means greater network security because an attacker would need to control more than 50% of the total computational power to execute a so-called 51% attack. This makes it extremely expensive and impractical to tamper with the blockchain on high-hash-rate networks.
For individual miners, hash rate determines profitability. A more powerful mining rig produces more hashes per second, increasing the likelihood of solving a block and earning the block reward. However, higher hash rates also mean higher electricity costs, making energy efficiency a critical factor.
Investors and analysts track network hash rate as a health indicator. Rising hash rate signals growing confidence in the network, while a sharp decline may indicate miners leaving due to low profitability or regulatory pressure.