₿Everything
Bitcoin

Bitcoin is digital money that people can send to each other online without a bank or payment company in the middle. The rules are enforced by open-source software run by thousands of independent computers.

Next step: Learning hub →

Before Bitcoin, sending money online always needed a trusted middleman, such as a bank or payment company, to stop people spending the same digital money twice. The white paper (2008) solved this double-spend problem with a public ledger secured by proof-of-work, so people can pay each other directly with no trusted third party. No central bank or company can print more: issuance follows a fixed schedule capped at 21 million (Bitcoin Core validation.cpp). No single party can freeze an account or block a valid payment, because thousands of independent nodes check the rules and any miner can include it. And you can hold it yourself: whoever controls the private keys controls the coins, so with self-custody you don't need anyone's permission to keep or send it.

Next step: The white paper, summarized →

Yes. One bitcoin is divided into 100,000,000 satoshis, or sats, the smallest unit in the protocol (Bitcoin Core, COIN constant in amount.h). Most exchanges let you buy small dollar amounts, often a few dollars at a time. Many people buy a small fixed amount every week or month, called dollar-cost averaging (DCA); try our DCA calculator, and see how to buy when you're ready.

Next step: How to buy →

Some criminals use it, but far more crime runs through ordinary money. Chainalysis estimates that illicit addresses received at least $154 billion in crypto in 2025, yet that was still below 1% of all attributed crypto transaction volume (Chainalysis 2026 Crypto Crime Report). By comparison, the UN Office on Drugs and Crime estimates that 2 to 5% of global GDP, or $800 billion to $2 trillion, is laundered each year (UNODC). The US Treasury's 2022 risk assessment found that the use of virtual assets for money laundering "remains far below that of fiat currency and more traditional methods" (Treasury, 2022 National Money Laundering Risk Assessment). Banks are not immune: in 2024 TD Bank pleaded guilty to Bank Secrecy Act and money-laundering conspiracy charges and agreed to pay about $1.8 billion in penalties (DOJ). The misuse of crypto is real, including ransomware, scams and sanctions evasion, and the same report covers it. But Bitcoin's ledger is public, which helps investigators: in 2022 US agents seized more than 94,000 bitcoin stolen in the 2016 Bitfinex hack (DOJ). Most people use Bitcoin to save, send money across borders, or hold an asset no one can print. See also: Is Bitcoin anonymous?

Next step: Is Bitcoin anonymous? →

No, it is pseudonymous. Every transaction is recorded on a public ledger forever, and addresses are not names, but they can be linked to you. The white paper's Privacy section (section 10) says privacy comes from keeping public keys anonymous, and warns that some linking of addresses is unavoidable. If you buy on an exchange that checks your ID (KYC), it can tie your identity to the addresses you withdraw to, and chain analysis firms such as Chainalysis use patterns like which addresses are spent together to trace flows (Bitcoin Wiki: Privacy). Basic habits help: use a new receive address every time, run your own node (for example on a Start9 server) so your wallet doesn't reveal your addresses to someone else's server, and use coin control in Sparrow to choose which coins you spend together. Lightning payments are not recorded on the public chain one by one, which helps a little, but it is not full anonymity. Some privacy tools have drawn legal action: in 2025 the founders of the Samourai Wallet mixing service were sentenced for operating an unlicensed money transmitting business (DOJ). See also: Is Bitcoin for criminals? and What is Chainalysis?

Next step: Sparrow Wallet →

It was published under the pseudonym Satoshi Nakamoto, whose identity is still unknown. No company or government runs it: anyone can run the software, and a rule change only sticks if the people running it choose to adopt it.

Next step: History of Bitcoin →