Roughly every four years, or every 210,000 blocks, the number of new bitcoins created in each block is cut in half. This event is called the halving. It steadily slows the creation of new bitcoins until the 21 million supply limit is reached.
The most recent halving took place on April 20, 2024, at block 840,000, and cut the block reward from 6.25 to 3.125 BTC. The next halving is expected around April 2028, at block 1,050,000, when the reward will fall to 1.5625 BTC. The exact date depends on how quickly blocks are mined.
Halvings get a lot of attention because they reduce the flow of new supply. Past halvings have been followed by large price moves in both directions, but past performance does not predict future results. For every date, block reward and price so far, see our Bitcoin halving history.