What is a bitcoin halving?
A bitcoin halving (sometimes ‘halvening’) is an event where the reward for mining new blocks is halved, meaning miners receive 50% fewer bitcoins for verifying transactions. Bitcoin halvings are scheduled to occur once every 210,000 blocks – roughly every four years – until the maximum supply of 21 million bitcoins has been generated by the network.
Bitcoin halvings are important events for traders because they reduce the number of new bitcoins being generated by the network. This limits the supply of new coins, so prices could rise if demand remains strong. While this has happened in the months before and after previous halvings – causing bitcoin’s price to appreciate rapidly – the circumstances surrounding each halving are different and demand for bitcoin can fluctuate wildly.
When is the next bitcoin halving?
The next bitcoin halving is expected to occur in the week commencing 18 May 2020, when the number of blocks hits 630,000. It will see the block reward fall from 12.5 to 6.25 bitcoins. The exact date of the halving is not yet known as the time taken to generate new blocks varies, with the network averaging one block every ten minutes.
Bitcoin halvings: key events
| Event | Date | Block number | Block reward | Total new bitcoins between events |
| Bitcoin launches | 3 January 2009 | 0 (genesis block) | 50 new BTC | 10,500,000 BTC |
| First halving | 28 November 2012 | 210,000 | 25 new BTC | 5,250,000 BTC |
| Second halving | 9 July 2016 | 420,000 | 12.5 new BTC | 2,625,000 BTC |
| Third halving | Expected week commencing 18 May 2020 | 630,000 | 6.25 new BTC | 1,312,500 BTC |
| Fourth halving | Expected 2024 | 740,000 | 3.125 new BTC | 656,250 BTC |
| Fifth halving | Expected 2028 | 850,000 | 1.5625 new BTC | 328,125 BTC |
This list is not exhaustive. Bitcoin halvings will occur every 210,000 blocks until around 2140, when all 21 million coins will have been mined.