Halving

The initial subsidy in 2009 was 50 BTC per block and it halves every 210,000 blocks, going from 50 to 25 in 2012, to 12.5 in 2016, to 6.25 in 2020 and to 3.125 BTC in 2024. The process continues until around 2140, when the subsidy reaches zero and roughly 21 million BTC will have been issued. From then on, miners are funded only by transaction fees.

It is the basis of Bitcoin's predictable, decreasing supply, with no discretion from any authority. New issuance is fixed in the code and the block pace is held steady by the difficulty adjustment, so the shrinking subsidy is the new portion of the block reward and is measured in satoshis. It is the mechanism that anchors the asset's scarcity narrative.

The verified data point is the fourth halving, which occurred at block 840,000 between 19 and 20 April 2024, around the UTC midnight crossover. It cut the subsidy from 6.25 to 3.125 BTC and reduced daily issuance from about 900 to about 450 BTC. The fifth halving is expected around April 2028, at block 1,050,000, dropping to 1.5625 BTC. That block 840,000 also coincided with the launch of Runes.