Difficulty adjustment

The difficulty adjustment is Bitcoin’s metronome: it sets how hard the proof-of-workGlossaryProof of workThe method by which miners prove that they have done real computing work for a new block. It lets the network agree on the valid chain without a central authority, and makes rewriting old blocks extremely expensive.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →× puzzle is.

How it works

Bitcoin Core sets ten minutes per block and an adjustment period of two weeks: 2,016 blocks × 10 minutes = 14 days.^[1] After every 2,016 blocks, each node uses the timestamps to check for itself how long those blocks took:

• faster than planned → the puzzle gets harder
• slower than planned → the puzzle gets easier
• Limit: In a single adjustment, the difficulty can at most quadruple or fall to a quarter.^[2]

There is no vote; all nodes reach the same result from the same data.

Why this matters

Without the adjustment, more mining machines would produce new bitcoin faster. As it is, the issuance schedule stays stable whether the hashrateGlossaryHashrate (computing power)How many hash attempts per second a mining device or the whole network makes. The network hashrate shows how much computing work secures Bitcoin.In the glossary →× rises or collapses. The four-year rhythm of the halvingGlossaryHalvingEvery 210,000 blocks – roughly every four years – the number of new bitcoin per block is cut in half. The fourth halving, on 20 April 2024, reduced it from 6.25 to 3.125 BTC.On the learning path: Stage 2 · Step 2 – Halving & 21 million →In the glossary →× depends on it too.

Current status

The difficulty is currently 132.7 T (T = trillion): that’s how many times harder the puzzle is than at the minimum difficulty of 1.^[3] The next adjustment comes in 1,669 blocks; based on the recent block pace, it is expected to change the difficulty by around +2.9% – an estimate that keeps shifting until then.