The process of reducing the Bitcoin mining reward by half is called “halving” or “halvening,” and it occurs approximately every four years. The halving is a predetermined event built into Bitcoin’s protocol, and it plays a crucial role in controlling the supply of new bitcoins entering circulation.

The primary metric used to determine when the next Bitcoin halving will occur is the number of blocks mined. Bitcoin’s blockchain is designed to produce a new block approximately every 10 minutes, and the mining reward is halved after every 210,000 blocks are mined.

Here are the key metrics related to Bitcoin halving:

1. Block Height: The block height is the number that identifies a particular block in the Bitcoin blockchain. The halving occurs at a specific block height, which is calculated based on the predetermined interval of 210,000 blocks.
2. Remaining Blocks until Halving: This metric tracks the number of blocks remaining until the next halving event. It is calculated by subtracting the current block height from the block height at which the next halving is scheduled to occur.
3. Time Remaining until Halving: Based on the average block time of 10 minutes, the remaining time until the next halving can be estimated by multiplying the remaining blocks until halving by 10 minutes.
4. Mining Reward: The mining reward is the amount of new bitcoins awarded to miners for successfully mining a block. This reward is halved after every 210,000 blocks. The initial mining reward was 50 bitcoins per block, and it has been halved three times so far, with the current reward being 6.25 bitcoins per block.
5. Total Bitcoin Supply: The total supply of bitcoins is capped at 21 million, and the halving events ensure that the supply gradually decreases over time until the maximum supply is reached, which is expected to happen around the year 2140.

 Bitcoin halving events occurred in the past, listed in the yyyymmdd format:

1. 20121128 – The first Bitcoin halving occurred on November 28, 2012, at block height 210,000. The mining reward was reduced from 50 bitcoins per block to 25 bitcoins per block.
2. 20160709 – The second Bitcoin halving took place on July 9, 2016, at block height 420,000. The mining reward was reduced from 25 bitcoins per block to 12.5 bitcoins per block.
3. 20200511 – The third Bitcoin halving occurred on May 11, 2020, at block height 630,000. The mining reward was reduced from 12.5 bitcoins per block to 6.25 bitcoins per block.

The next Bitcoin halving event is expected to occur around the following date:

4. 20240505 (approximately) – The fourth Bitcoin halving is estimated to happen around May 5, 2024, at block height 840,000. At this point, the mining reward will be reduced from 6.25 bitcoins per block to 3.125 bitcoins per block.

The halving events may vary slightly due to fluctuations in the Bitcoin network’s hash rate, which can affect the rate at which new blocks are mined. However, the halving events are predetermined to occur after every 210,000 blocks, ensuring a predictable and controlled supply of new bitcoins over time.

A simple strategy is to buy and hold Bitcoin for 1 month, 3 month, 6 month and 1 year each time the halving event occurs until present.