Bitcoin's mined supply crosses 95% of 21 million cap with more than a century of issuance left

Bitcoin crossed a major supply milestone on Monday, with mined coins surpassing 19.95 million BTC — equivalent to 95% of the network's fixed 21 million cap — according to onchain data.

Amid the gradual deceleration of new issuance as the network advances through successive halvings, less than 1.05 million BTC are left to be mined as block subsidy rewards until miners become solely reliant on transaction fees.

Notably, 230.09 BTC remains unspendable due to the genesis block subsidy and other outputs that were created with scripts that make them impossible to spend. Bitcoin's circulating supply does not take into account other coins that may have been lost by users who have misplaced their private keys.

Bitcoin circulating supply. Image: Bitbo.

Bitcoin's supply schedule is programmed to slow over time, with block subsidies cut in half every halving.

Bitcoin halvings are programmed to occur automatically every 210,000 blocks — roughly every four years. Once a halving event occurs, miners receive 50% fewer bitcoins as a subsidy reward for every block of transactions they mine and add to the blockchain. However, they continue to earn additional transaction fee rewards for each block mined as normal.

The fourth and most recent halving on April 20, 2024, reduced miner rewards from 6.25 BTC to 3.125 BTC per block, meaning that, on average, miners will now produce around 450 BTC in total per day compared to 900 BTC previously.

There have been three halving events in Bitcoin's history prior to that, reducing its block subsidy inflation from 50 BTC to 25 BTC in 2012, then to 12.5 BTC in 2016 and 6.25 BTC in 2020. The next halving is currently estimated for April 10, 2028, according to The Block's Bitcoin Halving Countdown page.

While the vast majority of BTC has already been issued, the remaining 5% will be released extremely slowly, with the last fractions expected to be mined around the year 2140 — roughly 115 years from today.

Long-term scarcity

This controlled issuance is central to Bitcoin's economic design. Each halving reduces the number of new coins entering the market per block, meaning the supply curve flattens sharply over time.

After the 2024 halving, the network’s annualized supply growth fell below 1% and will continue declining as future subsidy cuts take effect. Miners, who validate and secure the network, will increasingly rely on transaction fees as block rewards diminish.

Kraken Global Economist Thomas Perfumo told The Block that Bitcoin's predictable and declining issuance is a defining characteristic distinguishing it from traditional monetary systems.

"This programmable scarcity, coupled with predictable issuance and decentralized design, is what sets Bitcoin apart from competing forms of money and asset classes," he said. "In the short term, bitcoin's market price fluctuates with macro conditions that drive global markets, business cycles, liquidity trends, and investor sentiment. Over the long term, we believe bitcoin's hard money design, coupled with permissionless access and growing adoption, drive value accrual to the network." 

"It remains a natural hedge against fiat debasement and one of the few credibly neutral, globally accessible stores of value," Perfumo added. "For investors, it's a powerful diversification tool: a digitally native, non-sovereign, and borderless asset. As adoption deepens and regulation matures, bitcoin is increasingly viewed not as a speculative trade, but as a structural component of modern portfolios."