How many Bitcoins left to mine are there?
Last Saturday, 13th January, marked an important milestone for Bitcoin. 16.8 million coins were mined already, which accounts for 80% of the entire supply. This only leaves 4.2 million coins to be mined.
Why the cap?
The cap was introduced by Satoshi Nakamoto himself (themselves?) and mentioned in the 2008 White Paper. The goal was to create scarcity and therefore bring the price up. With the price of BTC reaching $20,000 last December – the plan seems to be working.
Currently, miners receive 12.5BTC reward for every block that they mine, but this changes approximately every 210,000 blocks (which works out to be approximately 4 years). Next halving will occur around early June 2020. The reward per block will be down to 6.25BTC then.