Bitcoin recently crossed a quiet but significant milestone:
20 million bitcoin have now been mined. That means more than 95% of all the bitcoin that will ever exist is already in circulation.
Only around one million bitcoin remain to be created, and that process will stretch out over the next century.
If you are relatively new to Bitcoin, those numbers might sound abstract.
But they're not.
Bitcoin's Fixed Supply: 21 Million, Full Stop
Bitcoin has a hard cap of 21 million coins. This isn't a target, a guideline, or a policy that some committee might revise next quarter. It is written into Bitcoin's code and enforced by every node on the network.
No government, central bank, CEO, or developer team can change it. To alter the supply cap, you'd need to convince the vast majority of Bitcoin's globally distributed network to agree: something that has never happened and, given the incentives at play, almost certainly never will.
Think of it this way: imagine you knew exactly how much gold existed on Earth, exactly where it was, and exactly when every gram of it would be dug up, down to the minute, for the next hundred years. That's essentially what Bitcoin gives you: complete transparency over its monetary supply, forever.
How We Got Here: The Halving Schedule
New bitcoin enters circulation through a process called mining. Miners use computing power to secure the network and validate transactions. In return, they receive a reward of newly created bitcoin with each block they add to the blockchain, roughly every ten minutes.
Here's the key mechanism: every 210,000 blocks (approximately every four years), that reward is cut in half. This event is known as the halving.
When Bitcoin launched in 2009, miners earned 50 BTC per block. After the first halving in 2012, it dropped to 25. Then 12.5 in 2016. Then 6.25 in 2020. After the most recent halving in 2024, the reward sits at 3.125 BTC per block.
The pattern is striking. In Bitcoin's first four years, over 10.5 million bitcoin were mined, half the total supply. It took just fifteen years to mine 95%. But the remaining 5% will trickle out over roughly the next one hundred years, with the final fraction of a bitcoin expected to be mined around the year 2140.
Each halving makes new bitcoin harder to come by. The flood becomes a stream, the stream becomes a drip.
Where Are Those 20 Million?
Here's something that surprises many newcomers: not all 20 million mined bitcoin are actually accessible.
Researchers estimate that between 3 and 4 million bitcoin are permanently lost. These are coins in wallets where the private keys have been forgotten, discarded, or destroyed. Early adopters who mined thousands of bitcoin in 2009 and 2010 sometimes stored their keys on old hard drives or computers that were later thrown away. Those coins still exist on the blockchain, but nobody can spend them. Ever.
Then there are Satoshi Nakamoto's coins. The pseudonymous creator of Bitcoin is estimated to hold around 1 million BTC, mined in the network's earliest days. These coins have never moved, and most analysts believe they never will.
When you account for lost coins, the effective circulating supply is likely closer to 16 or 17 million, making each accessible bitcoin even scarcer than the headline number suggests.
This is also a reminder of why self-custody and secure backups matter. Your bitcoin is only yours if you control the keys, and those keys are only useful if you can access them.
The Last Million: What Happens Next
With over 95% of bitcoin already mined, you might wonder what the future looks like.
The halvings will keep coming. By around 2032, the block reward will drop below 1 BTC. By 2040, more than 99% of all bitcoin will have been issued. The final coins will be mined in tiny fractions, with the reward eventually becoming so small it rounds to zero.
So what happens to miners when there are no more new bitcoin to earn?
This is where transaction fees come in. Every time someone sends bitcoin, they include a small fee to incentivise miners to include their transaction in a block. As the block reward shrinks, fees make up a growing share of miner revenue.
This transition isn't a flaw or an oversight, it is been part of Bitcoin's design since day one. Satoshi Nakamoto described it in the original white paper. The system was always meant to shift from subsidy-funded security to fee-funded security over time.
Why Scarcity Matters
To understand why 20 million out of 21 million is significant, it helps to look at how traditional money works.
The Australian dollar, like every fiat currency, has no supply cap. The Reserve Bank of Australia can expand the money supply whenever it deems it necessary, and it regularly does. Since 2020 alone, central banks around the world have created trillions of dollars, euros, pounds, and yen out of thin air.
The result is something every Australian has felt: your dollars buy less over time. The price of groceries, housing, and energy goes up not just because those things become more valuable, but because the currency you're measuring them in keeps losing purchasing power.
Bitcoin works in the opposite direction. Its issuance schedule is public, verifiable, and unchangeable. Anyone can check how many bitcoin exist right now, how many are being created per block, and exactly when the next halving will occur. You can audit Bitcoin's monetary policy yourself, try doing that with the RBA.
With a fixed supply and growing global demand, the fundamental equation is straightforward: the same amount of bitcoin, chased by more people, over a longer period of time.
What This Means for You
Every bitcoin you hold, whether it is a whole coin or a few thousand sats, represents a share of a capped supply. That share cannot be diluted. No one can print more bitcoin to fund a deficit, bail out a bank, or stimulate an economy.
This is why many Bitcoiners favour a long-term, consistent approach. Rather than trying to time the market, they dollar-cost average (DCA), buying a fixed amount of bitcoin at regular intervals, regardless of price. It's a strategy built on the simple logic that accumulating a scarce asset over time is fundamentally different from saving in a currency that loses value over time.
You don't need to buy a whole bitcoin. At the current exchange rate, most people stack satoshis, the smallest unit of bitcoin (one hundred millionth of a BTC). What matters isn't the size of each purchase, but the consistency.
20 Million Is More Than a Number
Bitcoin crossing 20 million mined isn't just a headline. It's a proof point. It proves that the system Satoshi Nakamoto set in motion in 2009 is working exactly as designed: predictably, transparently, and without anyone in charge.
The supply schedule hasn't been altered. The rules haven't been bent. The code keeps running, block after block, halving after halving.
In a world where monetary rules are routinely rewritten, that predictability is the point.
