The Bitcoin halving is a hard-coded rule that cuts the block reward in half every 210,000 blocks (~4 years). Starting at 50 BTC in 2009, the reward fell to 25 BTC in 2012, 12.5 BTC in 2016, 6.25 BTC in 2020, and 3.125 BTC in 2024. The purpose is to enforce a fixed total supply of 21 million BTC and gradually drive issuance toward zero. Halvings matter for the market because miner sell pressure from new issuance is also halved; if demand stays constant, supply-side pressure drives upward bias on price. Historically, the 2012, 2016, and 2020 halvings were followed by new all-time highs within 12-18 months, although the pattern is not guaranteed and macro conditions (rates, dollar index) remain decisive. Halvings also stress-test miner economics: high-cost or older-rig miners can become unprofitable and capitulate, briefly lowering hash rate before the difficulty adjustment rebalances. Litecoin, Bitcoin Cash, and other PoW coins have their own halving cycles.
Crypto Glossary
What is the Bitcoin Halving?
In Bitcoin and similar proof-of-work networks, a halving is the protocol-mandated reduction of the block reward by 50% roughly every four years.