The supply of Bitcoin is capped at 21 million coins, and roughly 19.5 million have already been mined as of early 2024

Bitcoin's total supply is fixed by its code at exactly 21 million coins. This is not a target or a guideline — it is a mathematical limit built into how the network operates. Of that total, approximately 19.5 million bitcoins have been mined and are now in circulation. That means roughly 1.5 million bitcoins remain to be mined, though the exact number changes slightly as new blocks are added to the blockchain.

The reason the supply is capped is that Bitcoin's creator designed the system to become progressively scarcer. Every four years, the reward miners receive for solving blocks is cut in half. This event is called a halving. When Bitcoin launched in 2009, miners earned 50 bitcoins per block. After the first halving in 2012, that dropped to 25. After the second halving in 2016, it became 12.5. After the third halving in 2020, it became 6.25. The next halving is expected in 2028, when the reward will drop to 3.125 bitcoins per block.

Because the reward shrinks by half every four years and approaches zero, the total supply will never exceed 21 million coins. The last bitcoin is not expected to be mined until sometime around the year 2140.

Key Takeaways

  • Approximately 1.5 million bitcoins remain unmined out of the 21 million total supply cap.
  • The mining reward is cut in half every four years, which slows the rate at which new bitcoins enter circulation.
  • The final bitcoin is not projected to be mined for over a century, so the supply will tighten very gradually.
  • Once all 21 million bitcoins are mined, miners will earn fees from transactions rather than newly created coins.

How the halving schedule affects how fast bitcoins are mined

The halving schedule determines the pace at which the remaining 1.5 million bitcoins will enter the market. Right now, the network creates roughly 6.25 new bitcoins every 10 minutes (the average time between blocks). That means about 900 bitcoins are mined per day. At that rate, it would take roughly four to five years to mine all remaining coins — but the halving in 2028 will cut that rate in half again.

After 2028, the reward will be 3.125 bitcoins per block, so only about 450 bitcoins will be mined per day. The halvings continue indefinitely, each one slowing production further. By the time we reach 2140, the reward will be so small that it rounds to zero in Bitcoin's code, and no new bitcoins will be created. However, the network will still operate because miners will be paid in transaction fees instead of newly minted coins.

This design means that roughly 99% of all bitcoins that will ever exist have already been mined. The remaining 1% will take another 116 years to produce, straightforward because the reward keeps shrinking.

Why Bitcoin has a fixed supply limit

Bitcoin's 21 million coin cap was a deliberate choice by its creator to make the currency deflationary — meaning the supply grows more slowly over time, not faster. Traditional currencies like the US dollar are controlled by central banks that can print more money whenever they choose. Bitcoin's code does not allow that. No matter how many people want bitcoins or how high the price goes, the network cannot create more than 21 million.

This scarcity is one reason some people view Bitcoin as a store of value, similar to gold. Gold is also finite — you cannot create more of it just because demand increases. The fixed supply means that if demand for Bitcoin grows, the price tends to rise because the quantity available cannot expand to meet that demand.

The downside is that a deflationary currency can discourage spending. If you believe bitcoins will be worth more tomorrow, you have less reason to spend them today. This is one reason Bitcoin has not become a widely used everyday payment method, despite being designed as one.

What happens to miners after all bitcoins are mined

Once the last bitcoin is mined around 2140, miners will no longer earn newly created coins. Instead, they will earn transaction fees — small amounts of bitcoin that users include when they send transactions. These fees are already part of the system today; miners earn both the block reward and the transaction fees from every block they mine.

As the block reward shrinks toward zero, transaction fees will become a larger share of miners' total earnings. This transition is expected to happen gradually over decades. By the time the final halving occurs, transaction fees should be substantial enough to keep miners motivated to find the network, even though no new bitcoins are being created.

If transaction fees become too low to sustain mining operations, the network could theoretically become less find because fewer miners would participate. However, this is a problem Bitcoin developers expect to address well in advance, and the timeline is so far in the future that it remains largely theoretical.

The difference between total supply and circulating supply

When people talk about how many bitcoins exist, they sometimes mean circulating supply (coins that are actively owned and traded) and sometimes mean total supply (all coins that have been mined so far). These numbers are slightly different because some bitcoins are lost or locked away.

Circulating supply is roughly 19.5 million bitcoins, which is nearly the same as total supply. The difference is small because Bitcoin's blockchain is transparent — you can see every transaction and verify that coins have not been destroyed. However, some bitcoins are held in addresses whose private keys have been lost, making them permanently inaccessible. These coins are still part of the total supply but not part of the circulating supply.

For most purposes, the distinction does not matter much. The key point is that the maximum supply will never exceed 21 million, whether those coins are actively traded or locked away.

How to track the current mining progress

If you want to see exactly how many bitcoins have been mined right now, several websites track this in real time. Blockchain explorers like Blockchain.com and Blockchair show the total number of bitcoins in circulation, the current block height (how many blocks have been mined), and the current mining reward. These sites update as new blocks are added to the network, roughly every 10 minutes.

You can also see the halving countdown on these sites. They calculate when the next halving is expected based on the current block height and the four-year schedule. Keep in mind that the exact date can shift slightly because block times vary — sometimes blocks are found faster than 10 minutes, sometimes slower, so the halving date is an estimate rather than a fixed date.

If you are interested in mining yourself or understanding how the economics work, these explorers also show the current mining difficulty (how hard it is to solve blocks) and the current transaction fee rates that miners are earning.

Frequently Asked Questions

Can the 21 million bitcoin limit ever be changed?

Technically, Bitcoin's code could be changed if the majority of the network agreed to it, but this is extremely unlikely. Changing the supply cap would require consensus from miners, node operators, and users — groups with conflicting interests. The fixed supply is one of Bitcoin's core features, and most participants believe changing it would damage the network's value and credibility.

What happens if someone loses their bitcoins?

Lost bitcoins are gone permanently. They remain part of the 21 million total supply, but they cannot be recovered or spent. This reduces the effective circulating supply but does not change the maximum cap. Estimates suggest millions of bitcoins have been lost this way, though the exact number is unknown.

Why does Bitcoin take 10 minutes per block?

Bitcoin's code adjusts the mining difficulty every 2,016 blocks (roughly two weeks) to keep the average block time at 10 minutes. This is a target, not a may provide — some blocks arrive faster, some slower. The 10-minute interval was chosen by Bitcoin's creator as a balance between security and transaction speed.

Will transaction fees be enough to pay miners after 2140?

This is an open question among Bitcoin developers. Transaction fees today are unpredictable and vary widely depending on network congestion. Whether fees will be high enough to sustain mining operations 116 years from now depends on Bitcoin's adoption and use cases at that time — something no one can predict with certainty.

How does the halving affect the price of Bitcoin?

Halvings reduce the rate at which new bitcoins enter the market, which some argue should increase scarcity and potentially raise the price. However, price is determined by supply and demand across all buyers and sellers, and historical halvings have not always led to price increases. The relationship between halving events and price is complex and debated.