Bitcoin's Supply Cap Is 21 Million. Millions of Those Coins Are Already Gone for Good
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5 min read
Bitcoin has a hard cap of 21 million coins. That number is in the code, and nobody can change it. But here is the part most people miss: not all 21 million will ever be spendable. A large slice is already locked in wallets that nobody can open.
So how many bitcoin are lost forever? The most-cited answer comes from the blockchain analytics firm Chainalysis, which estimated in June 2020 that about 3.7 million BTC had not moved in at least five years, close to 20% of the supply at the time (Decrypt). Later estimates sit lower, and the honest answer is a range, not a single number.
Let's walk through where the number comes from, and why nobody can prove it exactly.
First, a quick picture of the supply. The 20 millionth bitcoin was mined on 9 March 2026, so more than 95% of all bitcoin that will ever exist is already out there (CoinDesk). The last coin is not expected until around the year 2140.
Now the lost part. Published estimates from analytics firms run from about 2.3 million to about 3.7 million BTC lost, with some analysts using higher figures (as cited by BitGo and Ledger). Here is what that does to the supply, using simple subtraction on the 20 million mined:
| Scenario | Lost BTC | Coins that can still move | Lost share of the 20M mined |
|---|---|---|---|
| Low estimate | 2.3 million | about 17.7 million | about 11.5% |
| High estimate (Chainalysis, 2020) | 3.7 million | about 16.3 million | about 18.5% |
The last two columns are NetWort's own arithmetic on the published estimates. They are not figures any of those firms published themselves.
A bitcoin is not stored in a wallet like cash in a purse. It sits on the public ledger, and only someone with the matching private key can move it. A private key is a very long secret code that works like a password you can never reset. Lose it, and the coins stay on the ledger forever, visible but frozen.
There are four common ways that happens:
Two real cases show how this looks. In 2013, James Howells threw away a hard drive holding the key to 8,000 BTC that he had mined in 2009. It went to a landfill in Newport, Wales. In January 2025, the UK High Court dismissed his claim to dig it up, and the council owns anything sent to that landfill (Hausfeld).
Then there is Stefan Thomas, a programmer paid 7,002 BTC in 2011. He stored the key on an IronKey, a USB drive that wipes itself after 10 wrong password tries, and lost the paper with the password. Reports say he has used 8 of his 10 attempts (GNCrypto News). Those two people alone account for roughly 15,000 coins.
Here is the catch. The blockchain cannot tell the difference between a coin that is lost and a coin whose owner is simply patient.
Analysts use a shortcut: if a coin has not moved in a long time, it is probably lost. Chainalysis used five years. Glassnode, another on-chain data firm, tracks how old the untouched coins are. According to its supply-by-age data for 20 June 2026, as reported by BitGo, about 3.56 million BTC had not moved for more than 10 years, 1.69 million for 7 to 10 years, and 1.48 million for 5 to 7 years.
Add those up and you get more than 6.7 million BTC that have sat still for five years or longer. That is well above the loss estimates. The reason is that "untouched" and "lost" are different things. Some of those coins belong to long-term holders who are simply not selling. The estimated 1.1 million BTC in Satoshi Nakamoto's early wallets, which we cover in our look at whale wallet concentration, has not moved since 2010. Nobody outside knows whether the keys still exist.
That is why the honest range is wide. Any article that states "exactly 20% of bitcoin is lost" as a plain fact is claiming more than the data can show.
Satoshi Nakamoto thought so. On 21 June 2010, in a Bitcointalk thread called "Dying bitcoins," he wrote: "Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone."
The logic is simple supply and demand. Fewer spendable coins means each one is a little scarcer. But scarcity alone does not set the price. Demand does most of the work, and lost coins are a slow, invisible effect next to everything else that moves bitcoin. We covered a famous attempt to turn scarcity into a price forecast in why the stock-to-flow model failed.
There is also a practical lesson for anyone holding crypto: the same rule that makes bitcoin hard to seize makes it unforgiving to lose. If you keep coins yourself, the key is the whole game. We compare that trade-off with leaving coins on an exchange in this guide to exchange vs self-custody risk.
Lost coins are one reason a fixed supply cap is only half the story. To see how Bitcoin's price swings and worst drops compare with stocks, gold and other crypto, open Bitcoin's page on NetWort and look at its volatility and drawdown next to the other assets you track.
Sources retrieved 29 September 2026. Lost-coin figures are estimates from third-party analytics firms and change as methods change.