Bitcoin Difficulty Fell 9.29% as Miners Adjusted to the Halving

Bitcoin’s mining difficulty fell 9.29% at block 633,024 on June 4, 2020, making it easier for miners to produce valid blocks after the network ran more slowly than its intended pace. The adjustment reduced difficulty from approximately 15.14 trillion to 13.73 trillion at about 12:30 UTC.

The change was Bitcoin’s second consecutive downward retarget and followed the May 11, 2020 halving, which reduced the block subsidy from 12.5 BTC to 6.25 BTC. It was the second-largest difficulty decline of 2020 at that point, behind the 15.95% reduction on March 26.

What changed at block 633,024

Bitcoin recalculates its proof-of-work difficulty every 2,016 blocks, roughly once every two weeks. The protocol compares the elapsed timestamps for the completed adjustment interval with its target schedule of approximately one block every ten minutes. When blocks arrive too slowly, the next interval becomes easier; when they arrive too quickly, it becomes harder.

The difficulty before block 633,024 was approximately 15,138,043,247,082.88. The new value was approximately 13,732,352,106,018.34. Dividing the new figure by the old figure and subtracting one produces a calculated change of negative 9.2858%, conventionally rounded to a 9.29% decline.

Difficulty is a dimensionless protocol value derived from the proof-of-work target. It is not a direct measurement of electricity consumption, active mining machines or instantaneous network hashrate. Hashrate is estimated from the random pace of block discovery, while the difficulty applicable to a block is encoded through the target represented in its header.

The post-halving pressure

Bitcoin’s May 11 subsidy reduction cut the new bitcoin paid for each block in half without immediately changing mining difficulty. Operators still competed under the existing proof-of-work requirement until the next scheduled retarget. Difficulty then declined approximately 6% on May 20 and another 9.29% on June 4.

Those two reductions are consistent with less aggregate computing power competing during the completed adjustment windows. They do not identify which miners disconnected or why. Contemporaneous reporting connected the slowdown with older equipment becoming less economical after the halving, while also noting hardware shipments and the seasonal movement of machines toward lower-cost hydroelectric power in southwestern China.

Those explanations were industry observations, not facts encoded in the blockchain. Profitability depended on equipment efficiency, electricity prices, transaction fees, financing, uptime and bitcoin’s exchange value. The protocol record establishes slower block production and the resulting retarget; it does not provide a census of operators or their costs.

For miners that remained online, the lower difficulty improved expected block-winning odds for a fixed amount of computing power, all else equal. It did not restore the pre-halving subsidy, guarantee profitability or create additional demand for bitcoin. Each block continued to pay the scheduled 6.25 BTC subsidy plus its included transaction fees.

What the record supports

The defensible event-day conclusion is that Bitcoin automatically adapted to a post-halving reduction in effective mining competition. The adjustment demonstrated the protocol’s capacity to recalibrate without an administrator, emergency release or miner vote.

It did not establish that network security fell by exactly 9.29%, that every departing miner was inefficient, or that the retarget caused a market-price change. No bitcoin price, return or trading-volume claim is made because the cited event records do not provide a standardized exchange, currency pair and UTC measurement window capable of isolating a market reaction.