Bitcoin (BTC)

What Bitcoin is

Bitcoin is a digital currency that runs on a public blockchain with no company, bank, or government operating it. It was introduced by a person or group using the name Satoshi Nakamoto, who published the first Bitcoin specification and proof of concept in 2009 on a cryptography mailing list (source: bitcoin.org FAQ). Anyone can hold, send, and receive bitcoin using a wallet, and the supply is capped at 21 million coins.

Bitcoin was the first working answer to a problem that had defeated earlier digital cash designs: how to stop the same unit of money being spent twice without a central operator keeping score. Bitcoin's solution is a shared ledger that thousands of independent computers maintain and verify in parallel. That design is why bitcoin.org describes the network as one that "nobody owns" and that "is controlled by all Bitcoin users around the world."

If you are looking for where to buy Bitcoin, the exchange tables on this page and the listings across Exchanges cover which venues serve your country or state.

How it works

Bitcoin has four moving parts: wallets, transactions, the blockchain, and mining.

A wallet generates addresses you can hand out to receive payments. Bitcoin.org compares this to email, "except that Bitcoin addresses should be used only once." Each wallet also holds "a secret piece of data called a private key, which is used to sign transactions" (source: bitcoin.org). That signature is mathematical proof that the spender controls the coins, and it cannot be forged or altered after the fact. Lose the key and you lose the coins, which is why the seed phrase backup matters more on Bitcoin than almost anything else you will do with it.

A transaction moves value between addresses and is broadcast to the network. It is not settled the moment you send it. It has to be included in a block, and blocks are produced by miners.

The blockchain itself is, in bitcoin.org's words, "a shared public ledger that the entire Bitcoin network relies on." Every confirmed transaction is written into it, which is how wallets calculate balances and how nodes check that a spender actually holds what they are trying to send. The ledger is public, so anyone can audit it with a block explorer.

Mining is the part that turns a pile of broadcast transactions into settled history. Bitcoin.org calls it "a distributed consensus system that is used to confirm pending transactions by including them in the blockchain." Miners race to solve a computational puzzle; the winner proposes the next block and collects the reward. Because the puzzle is expensive to solve and trivial to verify, rewriting old blocks would mean redoing all that work faster than the rest of the network can extend the honest chain. Bitcoin.org notes that transactions are typically confirmed within 10 to 60 minutes and that new blocks arrive "approximately every 10 minutes on average," though the timing is probabilistic rather than guaranteed. This is proof of work, and it is what makes a double spend economically impractical.

The number of confirmation blocks you wait for before treating a payment as final is a judgment call. Exchanges usually publish their own requirement in their deposit documentation.

Supply and tokenomics

Bitcoin's monetary policy is fixed in software rather than set by a committee. Bitcoin.org states the design allows for "a total of 21 million bitcoins in existence" and that "bitcoins are created at a decreasing and predictable rate."

New coins enter circulation only as the reward paid to whoever mines a block, and there is no mechanism for anyone to issue more. Bitcoin.org describes the schedule plainly: "The number of new bitcoins created each year is automatically halved over time." That step-down is the bitcoin halving, and it is scheduled by block height rather than by calendar date, so it arrives whenever the network reaches the relevant block.

Two consequences follow. First, the circulating supply approaches the 21 million cap asymptotically and never exceeds it. Second, the share of miner income that comes from newly issued coins shrinks over time, and the share that comes from transaction fees grows. Whether fee income alone will be enough to secure the network in the distant future is an open engineering debate, not a settled fact, and anyone telling you otherwise is guessing.

Bitcoin's smallest unit is the satoshi. Amounts are divisible to eight decimal places, so the fixed cap does not limit how small a payment can be.

History

Bitcoin's public history begins with the specification Satoshi Nakamoto circulated on a cryptography mailing list, which bitcoin.org dates to 2009. Nakamoto worked on the software with a small group of contributors and then, per bitcoin.org, "left the project in late 2010 without revealing much about himself." The site takes a deliberately dismissive line on the identity question, arguing it is "probably as relevant today as the identity of the person who invented paper."

What followed was not a company launch but the slow accretion of an open-source project. Development moved to a distributed group of contributors, exchanges and wallet software grew up around the protocol, and mining shifted from ordinary CPUs to purpose-built hardware. Bitcoin.org is explicit that no single party can push a change through: modifications require broad agreement among users, miners, and node operators, and "all users are in full control of what Bitcoin software they use." That is why contentious upgrades have sometimes produced a fork rather than a clean migration.

Risks and what to watch

The most common way people lose bitcoin is not a market event. It is losing control of keys. If you hold your own coins, the seed phrase is the whole security model, and a hardware wallet plus an offline backup is the standard mitigation. If you leave coins on an exchange, you are trusting that venue's custodial arrangements, and RampAtlas tracks whether an exchange publishes proof of reserves on its exchange page.

phishing remains the highest-volume attack against ordinary holders. Fake wallet apps, fake support agents, and fake exchange login pages all target the same thing.

On the network side, watch the concentration of mining capacity, the long-run transition from block subsidy to fee income, and how the largest jurisdictions treat mining and self-custody. Bitcoin's volatility is a documented feature of its history rather than a bug that has been fixed, and it applies to every holding period.

RampAtlas does not tell you whether to buy Bitcoin. It tells you where you can, from where you live, and what the purchase is likely to cost.

Frequently asked questions

Who controls Bitcoin?

No one. Bitcoin.org states that "nobody owns the Bitcoin network" and that it "is controlled by all Bitcoin users around the world." Developers propose changes, but they cannot force adoption, because users and node operators choose which software to run. Miners order transactions but cannot change the rules unilaterally.

How many bitcoins will there ever be?

21 million. Bitcoin.org describes this as the total that will exist, reached through a creation rate that is "decreasing and predictable" and halves over time. There is no process by which holders, developers, or miners can issue more.

How long does a Bitcoin transaction take to confirm?

Bitcoin.org says transactions are typically confirmed in 10 to 60 minutes, with new blocks arriving roughly every 10 minutes on average. The exact time depends on network demand and the fee attached to your transaction. Exchanges set their own confirmation requirements for crediting deposits.

What is the difference between holding Bitcoin on an exchange and in your own wallet?

An exchange holds the keys on your behalf. self custody means you hold them yourself, using a hot wallet or cold wallet, and you carry full responsibility for backups. Each model fails differently: exchanges can restrict withdrawals or fail outright, while self-custody has no recovery path if the seed phrase is lost.

Where can you buy Bitcoin?

Availability depends on your country or US state, because exchanges license and restrict access regionally. See where to buy Bitcoin for the venues that serve your jurisdiction, or browse Exchanges to compare them directly.