Although a maximum of 21 million bitcoins can be minted, it’s likely that the number of bitcoins circulating remains substantially below that number. Bitcoin holders can lose access to their bitcoins, such as by losing the private keys to their Bitcoin wallets or passing away without sharing their wallet details. A June 2020 study by the crypto forensics firm Chainalysis estimates that up to 20% of the Bitcoin already issued may be permanently lost.4
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 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.1
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. If the Bitcoin blockchain in 2140 processes many transactions, then Bitcoin miners may still be able to generate profits from only transaction processing fees.
If Bitcoin in 2140 largely 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 can charge high transaction fees to process high-value transactions or large batches of transactions, with more efficient “layer 2” blockchains like the Lightning Network working in conjunction with the Bitcoin blockchain to facilitate daily bitcoin spending.
But if Bitcoin mining in the absence of block rewards ceases to be reliably profitable, then some negative outcomes can occur:
- Miners form cartels: Groups of miners may collude in an attempt to control mining resources and command higher transaction fees.
- Selfish mining occurs: Miners engaging in selfish mining collude to hide new valid blocks and later release them as orphan blocks that are not confirmed by the Bitcoin network. This practice can increase block processing times and ensure that high fees are paid for the new blocks when they are finally released to the blockchain.5
The Bottom Line
Will Bitcoin function like pocket change or bars of gold in the year 2140? The Bitcoin ecosystem is still developing, making it possible if not likely that Bitcoin itself will continue to evolve over the coming decades. But however Bitcoin evolves, no new bitcoins will be released after the 21-million coin limit is reached. Reaching this supply limit is likely to have the biggest impact on Bitcoin miners, but it’s possible that Bitcoin investors could experience negative impacts as well.
How Many Bitcoins Have Been Mined?
As of January 2022, 18.9 million bitcoins have already been mined, with about 2.1 million bitcoins still to be released. The total Bitcoin supply is capped at 21 million.3
How Long Does It Take to Mine One Bitcoin?
The length of time it takes to mine one Bitcoin depends on the amount of the block reward, or how many new Bitcoins are paid to crypto miners for generating a new Bitcoin block. The current block reward is 6.25 Bitcoins, and a new block is produced approximately every 10 minutes. A new bitcoin is mined on average every 1.6 minutes.12
What Happens to Mining Fees When Bitcoin’s Supply Limit Is Reached?
Bitcoin mining fees will disappear when the Bitcoin supply reaches 21 million. Miners will likely earn income only from transaction processing fees, rather than a combination of block rewards and transaction fees.