The block reward is how new Bitcoin enters circulation and how miners are incentivised to secure the network. It consists of the block subsidy (newly minted coins) plus transaction fees. The subsidy halves every 210,000 blocks — roughly every four years — in an event known as the halving. This predictable, diminishing issuance schedule ensures Bitcoin's supply approaches its 21 million cap asymptotically, with the final coins expected to be mined around the year 2140.