Halving

Bitcoin's code sets a hard limit of 21 million coins that can ever exist. To approach that cap gradually rather than all at once, the protocol automatically reduces the reward paid to miners by 50% after every 210,000 blocks are added to the chain — an interval that works out to approximately four years at normal processing speeds. This reward is the primary mechanism through which new bitcoins enter circulation, so the halving directly slows the rate of new supply.

To make it concrete: suppose miners currently earn a hypothetical 6.25 bitcoins per block. After the next halving, that drops to 3.125 per block. The total number of coins already in existence is unaffected; only the pace of new issuance changes. This is different from a stock split or a currency redenomination — existing holders see no mechanical change to their balance.

Halvings are fully predictable in schedule because the block count is public and the rule is written into the protocol. Traders and analysts typically watch halving dates because they alter the rate at which new supply enters the market, a dynamic discussed in the Bitcoin explained guide and explored through historical price cycles in crypto market cycles. The event recurs until all 21 million coins have been mined, which is projected to occur around the year 2140.