Every 4 years approximately, the block mining reward is halved. THE programmed scarcity mechanism of the Bitcoin protocol. History, price impact, dates of the 5 past and future halvings, 4-year cycles.
The halving (or "halvening") is a Bitcoin protocol-programmed event that halves the miner reward per block every 210,000 blocks, roughly every 4 years.
At Bitcoin's creation in 2009, the reward was 50 BTC per block. Since then: - November 2012: 50 → 25 BTC - July 2016: 25 → 12.5 BTC - May 2020: 12.5 → 6.25 BTC - April 2024: 6.25 → 3.125 BTC - ~April 2028 (next): 3.125 → 1.5625 BTC
This mechanism is THE key to Bitcoin's programmed scarcity: new supply decreases over time, converging toward the absolute cap of 21 million BTC (reached around 2140). That's what differentiates Bitcoin from fiat currencies printable at will by central banks.
Each halving has been followed by a "bull market" then "bear market" cycle of about 4 years, with a peak typically 12-18 months after the halving.
2012 cycle: halving at ~$12, peak at ~$1,100 in November 2013 (×90). Bear market down to ~$200 in January 2015.
2016 cycle: halving at ~$650, peak at ~$19,500 in December 2017 (×30). Bear market down to ~$3,200 in December 2018.
2020 cycle: halving at ~$8,600, peak at ~$69,000 in November 2021 (×8). Bear market down to ~$15,500 in November 2022.
2024 cycle: halving at ~$64,000, peak already at ~$108,000 in January 2025, then new ATH ~$125,000 in October 2025. Cycle to be watched.
Observable trend: cycles produce weaker peak multipliers over time (×90, ×30, ×8, ×2-3 expected) as Bitcoin market cap grows. It's mathematically logical: multiplying $100B by 90 is harder than multiplying $1B by 90.
The halving cuts miner revenue by 50% (in BTC terms). If BTC price doesn't compensate the decline, the least profitable miners (old gear, expensive electricity) are forced to shut down. That mechanically drops the network "hashrate" (computing power) for a few weeks.
In practice, the Bitcoin network self-regulates via "difficulty adjustment": every 2,016 blocks (roughly every 2 weeks), mining difficulty automatically adjusts to maintain an average block time of 10 minutes. If miners leave, difficulty drops and remaining miners become profitable again.
Long-term, as the block reward decreases, miners are funded increasingly by transaction fees paid by users. That's the planned final economic model: when the last BTC is mined around 2140, miners will live entirely on transaction fees. Everything depends on there being enough network activity to keep it profitable.
