The 21 Million Cap
There will only ever be 21 million bitcoins. This hard-coded limit is enforced by the Bitcoin protocol and cannot be changed without a near-consensus upgrade across the network. As of mid-2025, roughly 19.7 million bitcoins are in circulation, which means less than 1.3 million remain to be issued. The exact circulating supply fluctuates slightly because lost coins are permanently removed from active use, even though they still count toward the total supply figure.
More from this site
Keep reading the latest coverage
How Mining Releases New Bitcoins
New bitcoins enter circulation through mining, where nodes compete to validate blocks of transactions. Miners receive a block reward for each new block, and this reward halves approximately every four years, or every 210,000 blocks. The most recent halving in April 2024 cut the block reward from 6.25 BTC to 3.125 BTC. Because the schedule is predictable, the final bitcoin is expected to be mined around the year 2140, after which no new supply will enter the network.
Why the Supply Matters
The fixed supply is central to Bitcoin's value proposition. Unlike fiat currencies, which central banks can print in unlimited quantities, Bitcoin's scarcity is enforced by mathematics and consensus. This scarcity is why many investors treat bitcoin as a hedge against inflation and a digital store of value. The circulating supply number is publicly verifiable on the blockchain at all times.
Lost Coins and Effective Supply
While about 19.7 million bitcoins are technically circulating, the effective supply is lower because some coins are permanently lost. Users lose access when private keys are forgotten, hardware wallets are destroyed, or funds are sent to unspendable addresses. Estimates vary, but researchers believe between 2 million and 5 million bitcoins may already be lost forever, meaning the truly available supply is smaller than the headline circulating number.