A specific number of Bitcoins is generated each time a new block is mined. Halving is the process that enables Bitcoin to control its supply and by which this number is cut in half. This halving is scheduled in height (The block height of a particular block is defined as the number of blocks preceding it in the blockchain) and not in date. A halving occurs every 210,000 blocks. Once the block subsidy expires, miners will be paid for securing the network by transaction fees.

The first block in the bitcoin blockchain, the genesis block, was mined by Satoshi Nakamoto on January 3, 2009 at 18:15:05 (GMT) with a reward of 50 Bitcoins. New 50 Bitcoins were then issued every 10 minutes until the mining of the bloc 210,000 on November 28, 2012 at 15:24:38 (GMT). This block was mined by Slush's Pool by a miner called laughingbear using a Raedon HD 5800 Series graphics card. The reward dropped to 25 bitcoins until the block 420,000 was mined on July 9, 2016, date of the second halving and bitcoin reward halved a second time to become 12.5 bitcoins which is the current bitcoin block subsidy.

  Raedon HD 5800 Series graphics card.

The third halving will occur on 2020 when the bloc 630,000 will be mined and the subsidy will drop to 6.25 bitcoins/block and the the fourth halving is expected to occur between March 2024 and June 2024.

The total bitcoins to ever be produced is 21,000,000 and they will all be mined by 2140 but by 2030, more than 98% will be mined.

Currently, the number of bitcoins in circulation is 17,717,563 representing 84.37% of the total number of bitcoins.

Approximately 144 blocks are added each day to the bitcoin blockchain and the number of blocks needed until the next halving is currently 52,595.

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