What is the halving?

Bitcoin creates new coins by paying them to whoever adds a block. The payment started at 50 bitcoin per block in 2009 and halves every 210,000 blocks, which at roughly ten minutes per block works out to about four years.

50 in 2009. 25 in 2012. 12.5 in 2016. 6.25 in 2020. 3.125 since April 2024. The next halving, to 1.5625, is expected in 2028. Continue this and total issuance converges on 21 million coins around 2140.

Why it exists

A new network needs to distribute coins to the people securing it, and it needs to stop eventually if scarcity is the point. A geometric decay does both: generous early, negligible later, with a hard ceiling. The schedule is the monetary policy, and it is enforced by code rather than by a committee.

Current issuance is about 450 new coins a day against roughly 20 million in circulation, which is annual supply growth under one percent, below the typical growth of the above-ground gold supply.

What it does to miners immediately

Revenue per unit of work halves overnight while electricity bills do not. The least efficient machines become unprofitable and switch off, network hashrate falls, and difficulty adjusts downward within about two weeks so that the survivors' economics recover. Our mining calculator shows exactly where that break-even sits for any electricity price.

What it does to the price

Honestly: nobody knows. Each of the first three halvings was followed within a year or so by a large rise and then a deep fall. That is three observations over twelve years, each with a completely different economic backdrop, and it is not enough to establish a causal pattern.

There is also a theoretical objection. The halving is the most predictable supply event in any market. An efficient market would price it years ahead, and the fact that it seems not to is either evidence of inefficiency or evidence that something else was driving those cycles. The longer discussion is in our read on the four-year clock.

What happens at the end

Around 2140 the reward rounds to zero and miners are paid only from transaction fees. Whether fees alone can fund enough security is a genuine open question about the design, and it will not be answered for a very long time.