What is the maximum total supply of bitcoins?

The maximum total supply of bitcoins is 21 million BTC.

That limit is enforced by Bitcoin’s issuance rules rather than by a central bank or company. New bitcoins enter circulation as mining rewards: miners receive a block subsidy for adding valid blocks to the blockchain. The subsidy began at 50 BTC per block and is cut in half every 210,000 blocks, approximately once every four years.

Because each halving rounds the subsidy down in the smallest unit, the precise eventual issuance is slightly below 21 million: about 20,999,999.9769 BTC. The final subsidy-producing block is expected around 2140, assuming the protocol’s monetary rules remain unchanged.

A common mix-up is confusing maximum supply with circulating supply. Coins can be lost when private keys disappear, reducing spendable bitcoin without increasing the protocol limit. Fees also do not create new coins; only the block subsidy does. The 21-million figure applies to bitcoin itself, not to every cryptocurrency or to bitcoin forks such as Bitcoin Cash.