What Is Hashrate? How to Read TH/s and Bitcoin Hashrate
Hashrate, also written hash rate, is a measure of computing speed that counts how many hash calculations a machine or an entire proof-of-work network, such as Bitcoin, performs each second. Hashrate is counted in hashes per second (H/s), and Bitcoin mining machines are rated in terahashes per second (TH/s). More hashes per second mean more chances to find a block.
What Is a Hash, and Why Do Bitcoin Miners Make Trillions of Them?
A hash is the fixed-length output of a hash function, a calculation that turns any input into a result of the same size. The same input always produces the same hash. Changing a single character of the input produces a new hash that looks unrelated to the old one, so nobody can predict a hash without computing it.
Bitcoin uses a hash function called SHA-256, which produces a 256-bit result, written as 64 hexadecimal characters. Bitcoin miners run SHA-256 twice over the block header, an 80-byte summary of a candidate block. The header holds a reference to the previous block, a fingerprint of the block’s transactions, the time, and a 32-bit number called the nonce.
Proof of work is the rule that makes Bitcoin miners repeat the SHA-256 calculation of the block header. A block is valid only if its header hash, read as a number, is at or below a threshold called the target. Finding a valid hash takes an enormous number of attempts, while checking one takes a single hash.
Bitcoin miners change the nonce and hash the header again for each attempt. When every nonce value has been tried, they change the time field, or they change a second counter called the extra nonce. The extra nonce sits in the block’s first transaction, so changing it changes the transaction fingerprint in the header and gives the miner a fresh set of nonce values to try.
Hashrate counts hash attempts per second. Each hash is one guess, so a hashrate figure tells you how many guesses a machine makes every second. “Hashing power” is another name for hashrate.
An ASIC (application-specific integrated circuit) is a chip designed for one particular use rather than for general-purpose computing. A Bitcoin ASIC is built for Bitcoin’s SHA-256 hashing. ASICs far outperform the central processing units (CPUs) and graphics processing units (GPUs) in ordinary computers in both speed and energy efficiency, and today’s Bitcoin mining hardware is built on them. A single ASIC miner makes trillions of guesses per second.
How Is Hashrate Measured? From H/s to ZH/s
Hashrate is measured in hashes per second (H/s). Each unit up the scale is 1,000 times the one before it, following the standard metric prefixes, so 1 kH/s is 1,000 hashes per second and 1 TH/s is 1 trillion hashes per second.
| Unit | Name | Hashes per second |
|---|---|---|
| H/s | hash per second | 1 |
| kH/s | kilohash per second | 1,000 |
| MH/s | megahash per second | 1 million |
| GH/s | gigahash per second | 1 billion |
| TH/s | terahash per second | 1 trillion |
| PH/s | petahash per second | 1 quadrillion |
| EH/s | exahash per second | 1 quintillion |
| ZH/s | zettahash per second | 1 sextillion |
As of October 2026, a current Bitcoin ASIC miner is rated in the hundreds of TH/s, and Bitcoin hashrate across the whole network is on the order of 1 ZH/s.
TH versus TH/s: A Quantity and a Rate
TH/s, short for terahashes per second, is a rate. One TH/s means 1 trillion hashes every second. Bitmain’s Antminer S21 XP, rated at 270 TH/s as of October 2026, therefore computes about 270 trillion hashes each second.
TH on its own is used as a quantity of mining power. TH states how much mining power someone holds rather than quoting a speed, which is why the “/s” disappears. TH and TH/s describe the same capacity from two angles, and product documentation, GoMining’s included, uses both labels.
A digital bitcoin miner from GoMining is backed by mining power in physical data centers, and that mining power is measured in TH. GoMining’s documentation also describes the figure as the miner’s average hashrate in TH/s. In Mining mode, a digital miner’s rewards depend on how many TH it holds, are calculated once a day, and are paid in BTC. The rewards come from the mining pool that the miner’s owner selects.
A digital miner’s energy efficiency is measured in watts per TH (W/TH), and a lower figure is better. The daily maintenance fee covers electricity and equipment service and is deducted from the BTC rewards, so a lower W/TH means a smaller electricity part of that fee.
What Does Bitcoin Hashrate Tell You about the Network?
Bitcoin hashrate, also called network hashrate, is the combined speed of every machine mining Bitcoin. As of October 2026, Blockchain.com data put the 7-day average at about 1,010 EH/s, or roughly 1 ZH/s. That level sits below the peak 7-day average of about 1,152 EH/s that the same Blockchain.com series recorded in October 2025. Network hashrate rises when machines join the network and falls when they switch off.
One reason network hashrate falls is curtailment, which means that Bitcoin miners switch machines off or cut their power use on purpose for a while, for example when the electricity grid is under strain. In late January 2026, US miners powered down during Winter Storm Fern to ease the strain on the grid. Over the same week, Blockchain.com’s 7-day average fell from about 1,045 EH/s to about 826 EH/s, a drop of roughly a fifth. The Blockchain.com series had recovered to about 1,006 EH/s by mid-February 2026.
Network difficulty is a number that expresses how hard it is to find a valid block hash. Bitcoin aims for one block about every 10 minutes and recalculates difficulty every 2,016 blocks, which takes two weeks at that pace. When hashrate rises, blocks arrive faster than every 10 minutes until the next adjustment raises difficulty, and when hashrate falls, the reverse happens. For example, the 2,016 blocks before the mid-October 2026 adjustment took about 13.2 days instead of two weeks, so difficulty rose by about 5.9%.
Nobody measures network hashrate directly. Data providers estimate it from the current network difficulty and from how quickly recent blocks have arrived, and most smooth the result over several days. Because each provider uses its own method, the figures differ: single-day estimates from Blockchain.com and mempool.space for the same day in mid-October 2026 were about 7% apart.
Network hashrate is also a measure of how hard Bitcoin is to attack. An attacker with more than half of the network’s hashrate, the situation called a 51% attack, could rewrite recent blocks, reverse their own payments to spend the same BTC twice, and keep transactions from being confirmed. The higher the network hashrate, the more computing power an attacker would have to gather to reach that majority.
A 51% attacker still could not spend BTC that belongs to someone else, create BTC from nothing, or change how much new BTC each block creates, as long as users run full nodes that check every block against Bitcoin’s rules. Wallets that trust miners instead of checking blocks themselves are more exposed.
What Hashrate Does Not Tell You
Hashrate does not show what each guess costs in electricity, which is why spec sheets list power next to speed. As of October 2026, the specifications that the manufacturer Bitmain publishes for its Antminer S21 XP list a typical hashrate of 270 TH/s and a power draw of 3,645 W at the wall, measured with 25 °C inlet air. Bitmain gives a tolerance of plus or minus 3% on that hashrate and plus or minus 5% on that power.
Dividing a machine’s power draw by its hashrate gives its energy efficiency, written in watts per TH/s (W/TH). For the Antminer S21 XP, 3,645 W divided by 270 TH/s equals 13.5 W/TH. Bitmain lists the S21 XP’s efficiency as 13.5, and because a watt is one joule per second, that figure is the same as 13.5 J/TH. If TH/s is a machine’s horsepower, W/TH is its fuel consumption, and lower is better.
As of October 2026, Bitmain lists the older Antminer S19 XP at 141 TH/s and 3,031.5 W, which works out to 21.5 W/TH. For the same amount of work, the S19 XP draws about 59% more power than the S21 XP. Comparing the two machines by TH/s alone hides that gap. In this pair the faster machine is also the more efficient one, but a higher TH/s figure does not by itself make a machine the better one, because the electricity bill for each unit of work depends on W/TH.
A Bitcoin miner’s rewards depend on more than its own hashrate. When network hashrate grows, the same machine holds a smaller share of the total and wins a smaller share of the block rewards, and difficulty rises to match. Each block reward is made up of the block subsidy, which is newly created BTC, and the fees paid by the transactions in that block.
Bitcoin’s block subsidy has been 3.125 BTC since April 2024. When the chain reaches block 1,050,000, the subsidy halves to 1.5625 BTC, so every block pays half as much new BTC to whichever miner finds it, however much hashrate the network has. Rewards are paid in BTC, so their value in dollars moves with the BTC price, while the electricity bill depends on W/TH and the price of power.
Hashrate tells you how many guesses a machine makes, not what each guess costs or what it earns. With that in mind, you can read a spec sheet in TH/s and W/TH, read a network chart in EH/s, and know which questions hashrate cannot answer alone.
Related Terms
- Proof of work is the system Bitcoin uses to add blocks, in which miners repeat hash calculations until one result meets the target.
- Network difficulty is a number that expresses how hard it is to find a valid block hash.
- An ASIC (application-specific integrated circuit) is a chip designed for one particular use, and a Bitcoin ASIC is built for SHA-256 hashing.
- W/TH (energy efficiency) is the number of watts a machine uses for each TH/s of hashrate, and a lower figure means less electricity for the same work.
- A mining pool is a group of Bitcoin miners who combine their hashing work, and the pool credits that work to each member as shares and splits every block reward it wins according to each member’s contribution.
- Terahash per second (TH/s) is a unit of hashrate equal to 1 trillion hashes per second.
If you’re new to Bitcoin mining, you can continue with the Bitcoin and Mining course in GoMining Academy, a beginner course of seven lessons and a quiz.
November 27, 2025
