About every four years, the amount of new bitcoin miners earn per block gets cut in half. It makes new bitcoin harder to come by over time.
Go deeperHalvings happen every 210,000 blocks. The reward started at 50 BTC in 2009 and dropped to 3.125 BTC at the April 2024 halving. The next one is expected around 2028. As the reward shrinks, miners rely more on transaction fees.