What Is Hash Rate? Bitcoin Mining Power, Units and Difficulty

Hash rate is the number of hash calculations per second that miners perform while searching for a valid block. On Bitcoin, each calculation is a double SHA-256 hash of a block header, and the network’s combined hash rate, about 1,000 exahashes per second (10²¹ hashes every second) in October 2026 according to mempool.space, measures how much computing power stands behind the blockchain.

• Unit: hashes per second (H/s). Bitcoin’s network total is counted in EH/s, 10¹⁸ H/s.
• Estimated, not reported: nobody announces their hash rate; it is worked out from the difficulty and how fast blocks arrive.
• Tied to difficulty: every 2,016 blocks the target adjusts so that blocks keep coming about every ten minutes, whatever the hash rate.
• Security: rewriting confirmed blocks takes more hash rate than the rest of the network combined.
• Mining income: a miner’s expected share of block rewards equals its share of the network hash rate.

What Does Hash Rate Measure?

A miner looks for a block header whose hash, read as a number, falls below the network’s target. Hash outputs cannot be predicted, so the only method is trial and error: change a field called the nonce, hash the header again and check the result. The Bitcoin white paper describes proof of work as exactly this kind of scan, expensive to perform but checked with a single hash. Each attempt is one hash, and hash rate counts attempts per second.

Two different numbers go by the same name. A mining machine’s hash rate is its speed, printed on its spec sheet in terahashes per second. The network hash rate is the sum of every machine working on Bitcoin. Neither says anything about how many transactions Bitcoin can process: the block weight limit and the ten-minute target set that, and more hash rate only makes each block harder to find.

From H/s to ZH/s: Which Units Are Used?

Each step is a thousand times the one before it, so 1 EH/s equals a million TH/s.

How Is the Network Total Estimated?

Miners do not report their hash rate, but the blockchain gives it away. The difficulty, D, sets how many hashes a block takes on average: about D × 2³². At one block per 600 seconds, that implies a network hash rate of D × 2³² / 600 hashes per second, the formula the Bitcoin Wiki gives. After the adjustment at block 971,712 on 16 October 2026 the difficulty was about 1.406 × 10¹⁴, which works out to roughly 1.0 × 10²¹ hashes per second, or 1,000 EH/s.

Estimates also use how fast recent blocks arrived. Bitcoin Core’s getnetworkhashps command averages over the last 120 blocks by default, or over the blocks since the last difficulty change if you pass -1 (RPC reference). Because blocks are found at random, short windows swing a lot: mempool.space’s daily estimates ranged from about 940 to 1,080 EH/s between 14 and 18 October 2026. Charts based on three-day or seven-day averages are smoother, and two sites can disagree by several percent without either being wrong.

Why Does Mining Difficulty Change Every Two Weeks?

Every 2,016 blocks, about two weeks, each node compares how long those blocks took with the two weeks they should have taken and moves the target in proportion, by at most a factor of four in either direction (Bitcoin developer guide). If hash rate grew, blocks arrived early and the difficulty rises; if miners switched off, blocks slowed down and the difficulty falls. The 2,016 blocks before height 971,712 took about 13 days instead of 14, so the difficulty rose by 5.9%.

Between adjustments the lag shows. A quickly growing hash rate makes blocks come faster than every ten minutes, and a sudden drop makes them slower until the next retarget: in the week to 18 October 2026, miners found 1,074 blocks instead of the 1,008 a seven-day week should produce (mempool.space). This feedback loop keeps Bitcoin’s issuance on schedule no matter how much hardware joins or leaves. How Bitcoin mining works covers the rest of the process, from building a block to the hardware.

Why Does Hash Rate Matter for Security?

To reverse a confirmed payment, an attacker has to build an alternative chain with more accumulated work than the honest one, because nodes follow the chain with the most proof of work. Doing that reliably takes more hash rate than the rest of the network, the so-called 51% attack. With less, the odds collapse quickly: the white paper calculates that an attacker with 10% of the hash rate catches up from six blocks behind with a probability of about 0.024%, and that against an attacker with 30%, a recipient needs to wait for 24 confirmations to push the chance below 0.1%.

A high hash rate makes such an attack expensive, because the attacker would need machines and electricity on the scale of the whole network. Even a successful attacker could only reverse or reorder recent transactions, such as their own payments. They could not spend coins without the private keys, create coins beyond the subsidy or change the rules, because nodes reject invalid blocks however much work they carry.

The total hides how concentrated hash rate is. Most of it is pointed at a few pools: in the week to 18 October 2026, Foundry USA and AntPool together found 46% of all blocks (mempool.space). Pools coordinate miners rather than own all the machines, and miners can switch pools, but concentration is worth watching alongside the headline number.

How Much Can One Miner Expect to Earn?

A miner’s expected share of block rewards equals its share of the network hash rate. One machine at 200 TH/s against a network of 1,020 EH/s has a 1 in 5.1 million chance of finding any given block. At 144 blocks a day, mining alone it would expect one block every 97 years or so, which is why miners join pools that pay out in proportion to the work each member submits (Bitcoin developer guide).

The same ratio drives income. Revenue per unit of hash rate, often called hashprice, falls when the network grows faster than the bitcoin price or the fees users pay to get out of the mempool: at the October 2026 difficulty and the average reward of the preceding 1,008 blocks, one TH/s earned about 45 satoshis a day. Whether that covers the electricity bill is the subject of is Bitcoin mining still profitable.

Where Can You Check the Current Hash Rate?

• mempool.space mining dashboard: hash rate and difficulty charts, the estimated next adjustment and each pool’s share of recent blocks.
• Your own node: getnetworkhashps for the estimate and getmininginfo for the current difficulty.
• Compare like with like: a one-day figure and a seven-day average often differ by 5 to 10%, so check which window a chart uses before reading a record or a crash into it.

bitcoin-cli getnetworkhashps       # hashes per second over the last 120 blocks
bitcoin-cli getnetworkhashps -1    # since the last difficulty adjustment
bitcoin-cli getmininginfo          # includes the current difficulty

Hash rate is one of several public numbers that describe the network. For how it fits with the mempool, blocks and nodes, see how Bitcoin works.