A halving is a protocol-defined event in which a specified component of the reward for producing a block is reduced, often by approximately one half.

The term is especially associated with Bitcoin, where the block subsidy is periodically reduced. Because the subsidy is a source of new issuance, a halving reduces the rate at which new coins enter circulation.

Halving and mining

For miners, a halving directly changes mining economics. If the coin price, fees, and other parameters remain unchanged, a lower subsidy reduces revenue per successfully mined block.

Miners can offset part of the effect through changes in asset price, transaction fees, hardware efficiency, electricity costs, or operating conditions. The impact on an individual mining operation therefore depends on its cost structure and other variables.

Halving and supply

A halving does not destroy existing coins. It changes the future rate of issuance. It should therefore be distinguished from a token burn, which removes existing units from supply.