More specifically, Bitcoin Halving is an event that cuts the reward for mining Bitcoin transactions in half. This event occurs after every 210,000 blocks are mined, which is roughly every four years.
When Bitcoin was first introduced in January 2009, the block reward was set at 50 bitcoins. However, with each successive halving event, this mining reward decreases by 50%.
The first Bitcoin Halving took place on November 28, 2012, reducing the block reward from 50 bitcoins to 25. Subsequent halvings further reduced the reward to its current state.
Based on the current rate of halving, it is estimated that all 21 million bitcoins – the total supply limit set by Bitcoin’s creator – will be mined by the year 2140. The diminishing block reward and the finite number of bitcoins both contribute to the cryptocurrency’s deflationary nature.