The Halving: New Issuance Cut in Half Every Four Years

The Bitcoin network produces one block roughly every 10 minutes and pays newly issued bitcoin to the miner who creates that block. This reward is automatically cut in half each time the block height reaches a multiple of 210,000. Starting at 50 BTC in 2009, it became 25 BTC in 2012, 12.5 BTC in 2016, 6.25 BTC in 2020, and 3.125 BTC in April 2024.

Because mining difficulty is automatically adjusted roughly every two weeks to keep the average block interval at 10 minutes, the actual arrival of a halving follows a roughly four-year cycle, but the exact date shifts by a few days depending on mining speed. The next halving will occur at block 1,050,000 and is expected in the first half of 2028.

Under this rule, total issuance converges on 21,000,000 BTC. The last bitcoin is estimated to be mined around the year 2140, after which miners' income will consist solely of transaction fees rather than new issuance. Raising the issuance cap would require the vast majority of network participants to agree to a rule change — a change that would directly undermine the value of holders' assets, making it realistically very hard to achieve consensus on.

In all four halvings so far, the previous all-time high was broken within 12–18 months afterward. The simple logic often cited behind this pattern is that when new supply falls while demand holds steady or rises, price goes up.

However, the sample size is only four, and in each cycle variables other than the halving played a much larger role. The 2020 cycle had pandemic-response liquidity injections; the 2024 cycle had spot ETF approval. Any model that tries to explain price by the halving alone omits these variables.

Also, what the halving reduces is 'new issuance,' not the 'circulating supply.' The roughly 450 BTC issued daily is a very small share compared to the nearly 19.8 million BTC already in circulation. The halving's effect is less about an immediate supply shock and more a structural signal that the issuance rate keeps falling over the long run.

A halving means the mining industry's revenue is cut in half overnight. If price doesn't rise to match, mining rigs with lower power efficiency fail to break even and shut down. In practice, after every halving, hashrate has temporarily dropped and then recovered following a difficulty adjustment — a pattern that has repeated each time.

This process increases concentration in the mining industry. Only large operators with access to cheap power and the latest equipment survive, while small miners either join pools or exit the market. The geographic and corporate concentration of mining is a recurring point raised regarding the network's decentralization.