What Is Mining Difficulty and How Does It Work?

What is mining difficulty?

Mining difficulty is a number that tells miners how hard it is to find a valid block. To win a block, a miner must find a hash below a target; difficulty is how much smaller that target is than the easiest possible one. Bitcoin's difficulty of 148.36 T on 4 November 2026 means the network needs about 148.36 trillion × 2³² ≈ 6.4 × 10²³ hashes, on average, to find one block (AsicProfit network data; formula from the Bitcoin developer guide).

At the network's 1,026 EH/s that takes about 620 seconds, close to Bitcoin's 10-minute target.

Why does mining difficulty exist?

Difficulty keeps the pace of new blocks steady when miners join or leave. Without it, doubling the hashrate would halve the time between blocks and release new coins twice as fast. With it, the issuance schedule written into the protocol holds: on Bitcoin, 3.125 BTC per block since April 2024, plus fees.

How does a difficulty adjustment work?

Each network has its own rule for when and how much difficulty changes. Bitcoin and two common ASIC coins compare like this:

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On Bitcoin the rule is: new difficulty = old difficulty × (2,016 × 600 s) ÷ the time the last 2,016 blocks actually took. If those blocks took 13 days instead of 14, difficulty rises by 14 ÷ 13 − 1 = 7.7%.

What is the difference between hashrate and difficulty?

Hashrate is how much hashing the network does right now; difficulty is the network's response to it, set at the last adjustment. Hashrate is an estimate that jumps from day to day (AsicProfit's daily Bitcoin readings since 7 Oct 2026 range from about 900 to 1,240 EH/s); difficulty is an exact number that stays fixed for two weeks on Bitcoin. When hashrate rises, blocks come faster and the next adjustment raises difficulty. When hashrate falls, the reverse happens.

How does difficulty affect mining profit?

A miner's coin income falls in proportion to difficulty, as long as its own hashrate stays the same. Income is multiplied by old difficulty ÷ new difficulty.

A worked example with real numbers: the Antminer S21 XP (270 TH/s, 3,645 W) earned 1.00 unit of bitcoin at the 3 Oct 2026 difficulty of 132.72 T. At 148.36 T on 30 Oct it earns 132.72 ÷ 148.36 = 0.895 of that, 10.5% less bitcoin for the same machine and the same power bill. On 4 Nov 2026 it earns $9.24 a day before power.

A common mistake is to subtract the percentage directly. If difficulty rises 20%, income falls to 1 ÷ 1.2 = 83.3% of what it was, a fall of 16.7%, not 20%. A miner earning $25 a day would earn $20.83, not $20.

How has Bitcoin's difficulty changed in 2026?

Bitcoin's difficulty has moved in both directions in 2026, between a low of 124.93 T and a high of 148.36 T. Selected levels (AsicProfit network data):

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So difficulty does not only go up. Over the year to 4 Nov 2026 it is almost exactly where it started (+0.07%), even though it fell 16% in between. What it does over longer periods depends on new hardware and the coin price.

Does difficulty matter more than the coin price?

Neither always wins: income in dollars is coin income × coin price, so a 10% rise in difficulty and a 10% rise in price roughly cancel out. Between 3 Oct and 4 Nov 2026 Bitcoin difficulty rose 11.8% while the price moved from about $85,000 to $80,344, so both worked against miners. Difficulty changes are slower and easier to plan for: on Bitcoin you know two weeks ahead roughly what the next one will be.

What are the limits of this explanation?

Difficulty explains how much coin a machine earns, not whether mining is worth it. Power price, pool fees, downtime, the purchase price of the miner and the coin price all matter as much. A difficulty forecast is only a guess: it assumes the current block pace continues until the next adjustment.

For today's Bitcoin numbers and what may come next, see Bitcoin mining difficulty 2026: what comes next. The difficulty and hashrate history for each coin is on its calculator page, for example the Bitcoin calculator and the Zcash calculator; terms such as hashrate and J/TH are explained in the mining dictionary.

Updated 4 Nov 2026: today's Bitcoin difficulty added, 2026 timeline and adjustment-rule table added, worked example corrected (+20% difficulty = −16.7% income).