to those who is unfamiliar What is the Bitcoin halving -
To understand what The Bitcoin Halving is, you must first understand the basics. In short, new Bitcoins come into the world as a reward for miners whenever they mine a Bitcoin block.When Satoshi Nakamoto set up for the Bitcoin protocol he stated two important things, among others:
First, that the supply of Bitcoin is finite and limited to 21 Million.
Second, that the number of bitcoins generated per block i.e. the reward is set to decrease by 50% every 210,000 blocks. Since 6 blocks are found on average within an hour and halving happens once every 210,000 blocks, this means that every 4 years (give or take) there will be a halving event. This basically means that the mining reward will be reduced by 50% from what it used to be. For example, if today each miner receives 12.5 Bitcoins for solving a block, after the next halving event they will receive only 6.25 BTC and so forth.
Following this math, the final number of Bitcoins will be roughly 21 million (20999999.9769 to be exact) by the year 2140.