Bitcoin Hits 20M Coins Mined—Last 1M Will Take Over 100 Years
Bitcoin's supply hit a crossroads on March 9: the first 20 million coins took 17 years to mine, but the final 1 million will stretch beyond 2140. As block rewards halve every four years, miners are increasingly vulnerable to revenue cliffs unless transaction fees scale dramatically.
Key Takeaway
Bitcoin's shrinking block rewards are forcing miners into AI pivots while fee revenue stays too thin to secure the network.
Foundry USA mined the block that pushed Bitcoin past 20 million coins in circulation at block height 940,000, according to Mempool data.
The milestone exposes a structural tension in Bitcoin's design. Halvings occur every 210,000 blocks, cutting the block reward in half on a fixed schedule that no government or central bank can alter. The April 2024 halving dropped the reward from 6.25 BTC to 3.125 BTC. The last satoshis won't be issued until 2140.
Kraken Chief Economist Thomas Perfumo said Bitcoin stands as one of the few truly scarce assets, with its maximum supply mathematically bound unlike traditional currencies with unlimited supply. Metaplanet Founder Simon Gerovich called the final million the era when true digital scarcity begins.
But scarcity alone doesn't guarantee security. Miners collected an average of just 0.0192 BTC in transaction fees per block over the past week, a fraction of the 3.125 BTC block subsidy. Hashprice fell below ₱1,770 ($30) per petahash per second per day in late February, pushing breakeven miners toward the exit. The security model assumes transaction fees will eventually grow large enough to replace declining block subsidies, but that fee market remains too thin to cushion the reward decline.
Ethereum Foundation's Justin Drake argued in 2025 that Bitcoin's security model faces challenges if the fee market doesn't mature. Two counterarguments circulate in Bitcoin circles: rising Bitcoin prices will keep mining profitable, and the fee market will mature as more users, institutions, and layer-2 solutions come online.
Publicly traded miners like Core Scientific, Bitfarms, TeraWulf, CleanSpark, and Hut 8 announced ₱2.54 trillion ($43 billion) in AI and high-performance computing contracts over the past year, reframing themselves as energy and cooling infrastructure providers rather than pure Bitcoin producers.
This article was written based on reporting from CryptoSlate.
