Bitcoin’s (BTC) blockchain hit a unique milestone in April as the 17 millionth BTC was mined[1].
If you’re wondering why this number is significant, it’s because there are only four mln tokens left to mine before the 21 mln BTC cap is reached. However, the truth is that most people alive today are unlikely to see that happen.
Bitcoin’s blockchain protocol makes mining more difficult as more miners join the pool, and the Bitcoin reward for mining a block also halves every 210,000 blocks. As it stands, miners receive a 12.5 BTC reward for unlocking a new block. According to BitcoinBlockHalf.com[2], the next reward halving will happen in May 2020 - reducing the reward to 6.25 coins.
Assuming that there are no changes to the protocol, the Bitcoin cap will be reached by 2140, 122 years from now.
Nevertheless, it’s taken just 9 years to mine 80 percent of the total Bitcoin that will ever be available, in a little over 520,000 blocks, as shown in the graph below.
What happens when we mine the last Bitcoin?
Currently, miners are still heavily incentivized to mine in order to obtain increasingly more valuable Bitcoin tokens as a reward before the supply reaches its capacity.
But, when the day comes that the 21 mln cap is hit, there will be no more BTC rewards for miners. However, transactions still need to be validated and stored on blocks in the blockchain - so miners will only benefit from transaction fees.
As it stands, Bitcoin transactions are processed by the network in order of the transaction fee associated to that specific transaction. The higher the fee[3], the more incentive there is for a miner to prioritise your to be included in a block.
