What is the block reward halving schedule in Bitcoin?

The block reward halving schedule in Bitcoin is a predetermined event programmed into the Bitcoin protocol that reduces the reward given to miners for successfully mining a new block. This reduction occurs approximately every four years, or precisely every 210,000 blocks. The process is often referred to as "halving" because the reward is halved each time it occurs.

Here's a summary of the block reward halving schedule in Bitcoin:

1. **Genesis Block**: When Bitcoin was launched in January 2009, the initial block reward was 50 bitcoins per block.

2. **First Halving (November 2012)**: After approximately four years and 210,000 blocks, the block reward was reduced by half to 25 bitcoins per block.

3. **Second Halving (July 2016)**: Another four years and 210,000 blocks later, the block reward was halved again to 12.5 bitcoins per block.

4. **Third Halving (May 2020)**: Following the same pattern, the block reward was reduced to 6.25 bitcoins per block in May 2020.

5. **Future Halvings**: The block reward will continue to halve approximately every four years until it eventually reaches zero, at which point no new bitcoins will be minted, and miners will rely solely on transaction fees for income.

The block reward halving is an essential feature of the Bitcoin protocol designed to control the issuance of new bitcoins and ensure a finite and predictable supply. By gradually reducing the rate at which new bitcoins are created, the halving mechanism serves to curb inflation and prevent the devaluation of the cryptocurrency over time.

The halving events also have significant implications for the Bitcoin mining ecosystem. As the block reward decreases, miners' income from block rewards decreases, and they must rely more heavily on transaction fees to sustain their operations. This dynamic can impact miner profitability, influence mining hardware investment decisions, and contribute to changes in the distribution of hash power across the network.