The programmed 50% reduction in Bitcoin's block subsidy every 210,000 blocks.
Halving meaning
A halving cuts the new bitcoin available in each block while leaving transaction fees untouched. It is part of Bitcoin's consensus-enforced issuance schedule, not an event scheduled by an exchange, company, or government.
How it works in Bitcoin
Full nodes calculate the allowed subsidy from block height. The interval of 210,000 blocks is roughly four years at the target block pace, but the exact date is uncertain because block arrival is random.
A simple example
The subsidy moved from 6.25 BTC to 3.125 BTC at block 840,000 in 2024. A miner could claim fees on top of that amount.
Why Halving matters
Mining terms connect proof of work, block production, incentives and energy. They should not be used as shorthand for node validation or guaranteed profitability.
What people often get wrong
Past market behavior around halvings does not guarantee future price performance. Supply issuance is only one part of a market with changing demand, liquidity, and expectations.
Quick checks before using the term
- Is this about hashrate, energy, revenue or validation?
- Which unit and period does the claim use?
- What changes when difficulty or fees move?
Apply these questions to the concrete example above. A precise answer is more useful than repeating the definition without naming the actor, rule or failure path.
Check the primary reference
This entry is written in plain English, but the technical source is available when you need exact protocol detail.
Bitcoin Developer Guide: Mining ↗