The amount of bitcoin (BTC) that miners are paid, known as the block reward, decreases over time through a process called halving. Halving contributes to managing BTC's scarcity.
The first blocks of the Bitcoin blockchain generated block rewards of 50 BTC each. However, as of 2018, the block reward decreased to 12.5 BTC. The block reward is halved every 210,000 blocks (approximately every four years).
The total amount of BTC will never exceed 21 million. The last BTC will be mined around 2140.
