This limit is hardcoded into Bitcoin’s protocol by its creator, Satoshi Nakamoto, to make Bitcoin scarce—similar to gold. No more than 21 million Bitcoins will ever exist.
Currently (as of 2025), more than 19.7 million BTC have already been mined.
The last Bitcoin is expected to be mined around the year 2140, after which miners will only earn transaction fees.
What Happens After All 21 Million Bitcoin Are Mined?
After the maximum number of Bitcoins is reached, even if that number is ultimately slightly below 21 million, no new Bitcoins will be issued.
Bitcoin reaching its upper supply limit is likely to affect Bitcoin miners, but how they are affected depends in part on how Bitcoin evolves as a cryptocurrency. Bitcoin transactions will continue to be pooled into blocks and processed, and Bitcoin miners will continue to be rewarded, but likely only with transaction processing fees.
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If Bitcoin in 2140 essentially serves as a store of value rather than for daily purchases, then it's still possible for miners to profit—even with low transaction volumes and the disappearance of block rewards. Miners could charge high transaction fees to process high-value or large batches of transactions, with more efficient "layer 2" blockchains like the Lightning Network working with the Bitcoin blockchain to facilitate daily Bitcoin spending.
