What Is Bitcoin? Fixed Supply, Mining and Halving Explained
Lesson 2 of 10 · Beginner
What is Bitcoin and where did it come from?
Bitcoin was the first cryptocurrency to solve the “double-spending” problem of digital money without a bank or intermediary. A person or group using the pseudonym Satoshi Nakamoto published a short paper (the white paper) in 2008, and the network went live in January 2009. Bitcoin has no company, CEO or head office. It is open-source software run by thousands of nodes around the world, which enforce its rules together.
The smallest unit of bitcoin is the satoshi: one hundred-millionth of a bitcoin. So nobody has to buy or send “a whole bitcoin”; very small amounts are possible too.
A common but wrong belief is that Bitcoin is anonymous. Every transaction is recorded in the public ledger forever. Addresses do not carry names, but once an address is linked to a real identity (for example a verified exchange account), the path of the money can be traced. It is more accurate to call Bitcoin pseudonymous.
Fixed supply: the 21 million cap
Bitcoin has no central bank deciding how much money to print. The issuance schedule is written into the code from day one: new bitcoin is created only as the block reward paid to the miner who builds a new block, and the total of all rewards will never exceed about 21 million bitcoin. More than 90 percent of that amount has already been mined, and the rest will be released at a declining pace over more than a century.
What enforces the cap? The nodes themselves. Every node checks every block, and if a miner writes itself a larger reward than the rules allow, the block is rejected. Changing this rule would require extremely broad agreement among users and nodes, and that difficulty is part of Bitcoin's value proposition.
Two realistic caveats:
- A limited supply does not mean a guaranteed price. Price is set by supply and demand, and demand can swing sharply.
- Some bitcoin has probably been lost forever because keys were lost, but nobody knows the exact amount.
Mining and proof of work: why miners matter
A miner collects queued transactions, places them in a candidate block, and uses specialised hardware (ASICs) to compute billions of hashes per second, searching for a number that meets the network's condition. The first miner to find an answer publishes the block and receives two things: the block reward (newly created bitcoin) and the fees from the transactions in that block.
The network is designed to produce a block about every 10 minutes on average. If more miners join and blocks are found faster, every 2,016 blocks (roughly every two weeks) the network raises the difficulty; if miners leave, difficulty falls. That is why adding more miners does not create more bitcoin; it only makes the competition harder.
Why does this costly work matter? To rewrite history, an attacker would have to command more computing power than the rest of the network combined. The network's total computing power (the hashrate) is effectively Bitcoin's security budget. Miners pay this cost because they expect the reward and fees to cover it.
The halving: the reward is cut in half about every four years
Every 210,000 blocks, roughly every four years, the block reward is cut in half. This event is called the halving:
| Period | Reward per block |
| Network launch (2009) | 50 BTC |
| 2012 halving | 25 BTC |
| 2016 halving | 12.5 BTC |
| 2020 halving | 6.25 BTC |
| 2024 halving | 3.125 BTC |
With about 144 blocks per day, roughly 450 new bitcoin are issued each day after the 2024 halving. By the same rule, the next halving is expected around 2028, but the exact date depends on how fast blocks are produced.
Be careful with the “halving cycle” idea. The halving date is known to everyone years in advance, and there are only a handful of historical cycles; that is too small a sample to build a price rule on. Market conditions have also changed: ETFs, futures and large corporations now account for a significant share of demand.
The more important long-term question is whether, as the reward shrinks, fees can fund miners' security budget. That is an open debate with no settled answer.
A Bitcoin transaction in practice: fees and confirmations
When you send bitcoin, the transaction first enters a waiting queue called the mempool. Miners generally pick up first the transactions that pay a higher fee per unit of data size. So a Bitcoin fee does not depend on how much money you send; it depends on the data size of the transaction and how busy the network is at that moment. Sending a small amount during congestion can cost more than sending a large amount during a quiet period.
Once a transaction is included in a block, it has one confirmation, and each subsequent block adds another. Exchanges usually wait for several confirmations before crediting a deposit; each exchange sets its own number. If you set the fee too low, the transaction may sit in the queue for a long time. Some wallets let you bump the fee of a pending transaction, but a confirmed transaction cannot be taken back.
Common mistakes
- Believing a limited supply means the price can only go up; demand can also fall sharply.
- Assuming Bitcoin is fully anonymous; every transaction is public and traceable.
- Treating the halving as a buy signal with a known date, when only a few historical samples exist.
- Trusting adverts for “cloud mining”, “phone mining” or “USDT mining” with fixed returns; these are well-known scam patterns.
- Thinking more miners means more bitcoin is produced; the difficulty adjustment prevents that.
What do volume and data say here?
Bitcoin is one of the few assets whose supply side is fully transparent and open to anyone to check:
- Hashrate and difficulty: visible on public on-chain dashboards, they show how much computing power protects the network. They are indicators of security health, not price signals.
- Fees and the transaction queue: when demand for block space rises, fees rise. This data shows how congested the network is.
- ETF flows: an important part of today's demand comes from US-listed bitcoin exchange-traded funds. According to Farside data as reported by Ryder, these funds' net assets were about 106 billion dollars as of 9 October 2026. You can compare daily inflows and outflows with the roughly 450 bitcoin issued each day to get a feel for the scale of supply and demand.
An important warning: most of the “bitcoin trading volume” on exchanges comes from perpetual futures contracts, not spot buying. According to CryptoRank, Binance's spot volume was about 10 percent of its perpetuals volume. So high volume does not necessarily mean real buying and holding. This data gives context, not predictions.
📊 See real gold futures volume behind these ideas: free order flow course · today's gold volume map
Frequently asked questions
What is bitcoin in plain language?
It is digital money with no central bank, running on a network of thousands of independent computers. Supply is capped at about 21 million, and new bitcoin enters circulation only through mining, on a schedule written in advance.
What is the Bitcoin halving and when is the next one?
Every 210,000 blocks the miners' reward is cut in half. The last one, in 2024, took the reward from 6.25 to 3.125 BTC, and the next is expected around 2028. A halving is not a guaranteed date for a price rise.
Can you mine bitcoin on a phone?
Not in any meaningful way. Bitcoin mining is done with specialised hardware. Apps and sites promising “phone mining” or “cloud mining with fixed returns” follow a common scam pattern.
Education only, not a recommendation to buy or sell; we never give signals. Price examples are illustrative. Test any method on a demo account first, with strict risk management.