Bitcoin
Digital money without a central authority: thousands of independent computers check every transfer against the same open rules. The supply is permanently capped at just under 21 million BTC.
AlsoBTCXBT₿Bitcoin network
On the learning path: Stage 1 · Step 1 – Bitcoin in 10 minutes
Bitcoin is digital money without a bank, government or company in the middle. Payments go directly to the recipient and are checked by independent computers around the world, the nodesGlossaryNodeA computer that runs Bitcoin software and exchanges transactions and blocks with other nodes. Together, the nodes form the Bitcoin network; full nodes check every rule themselves.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →.[1]
How it all began
Under the pseudonym Satoshi NakamotoGlossarySatoshi NakamotoPseudonym of the person or group who invented Bitcoin. Satoshi published the whitepaper in 2008, launched the network in 2009 and withdrew in 2011. Who is behind the name remains unknown to this day.In the glossary →, a person or group described Bitcoin in the whitepaperGlossaryWhitepaper (Bitcoin whitepaper)The nine-page founding document in which Satoshi Nakamoto introduced Bitcoin on 31 October 2008. It explains how payments can work without a bank and how double spending is prevented.In the glossary → on 31 October 2008. The first block, the genesis blockGlossaryGenesis blockThe very first block of the Bitcoin blockchain, created on 3 January 2009. It contains a newspaper headline about bank bailouts – and its reward of 50 BTC can never be spent, for technical reasons.In the glossary →, was created on 3 January 2009.[1],[2]
What makes Bitcoin different
- No central authority: The rules are written in open software. Every node checks for itself whether transactions and blocks follow them.
- Public ledger: All transactions are recorded in the blockchainGlossaryBlockchainBitcoin’s public ledger: a chain of blocks in which each block refers to its predecessor. Anyone wanting to change an old entry would have to recreate all the blocks that follow it.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →, which anyone can inspect.
- Fixed supply: New bitcoin are created through mining on a fixed schedule, just under 21 million BTC in total.[3] So far, 20,093,887 BTC have been issued, or 95.69% of the total.
- Divisible: 1 BTC is 100 million satoshisGlossarySatoshi (sats)The smallest unit of Bitcoin: 1 satoshi (‘sat’ for short) equals 0.00000001 BTC, so one bitcoin consists of 100 million sats. The unit is named after Bitcoin’s creator, Satoshi Nakamoto.On the learning path: Stage 1 · Step 4 – Sats & units →In the glossary →.[4] So you don’t need to buy a whole bitcoin; one currently costs $85,533.
Bitcoin, BTC and ‘crypto’
‘Bitcoin’ means the network and the currency; ‘BTC’ is the unit, as in 0.01 BTC. Bitcoin was the first cryptocurrency; how later ones differ is explained in Bitcoin, not ‘crypto’.
Important: the price is highly volatile, transfers can’t be reversed, and you are responsible for the security of your bitcoin yourself. Overview: Bitcoin in 10 minutes.
Related terms
These terms are closely connected.
- This termBitcoin
- BlockchainBitcoin’s public ledger: a chain of blocks in which each block refers to its predecessor. Anyone wanting to change an old entry would have to recreate all the blocks that follow it.
- Satoshi (sats)The smallest unit of Bitcoin: 1 satoshi (‘sat’ for short) equals 0.00000001 BTC, so one bitcoin consists of 100 million sats. The unit is named after Bitcoin’s creator, Satoshi Nakamoto.
- 21 million (Bitcoin’s supply cap)Under the network’s rules, there will never be more than just under 21 million bitcoin. The cap follows from the issuance schedule: new bitcoin per block halve every 210,000 blocks until none are created, around 2140.
- DecentralisationBitcoin has no headquarters that could change the rules, freeze accounts or print more money. Instead, tens of thousands of independent nodes around the world check for themselves that all the rules are followed.
- NodeA computer that runs Bitcoin software and exchanges transactions and blocks with other nodes. Together, the nodes form the Bitcoin network; full nodes check every rule themselves.
Explained in depth
These articles go into more detail:
- Stage 1 · Step 2What is Bitcoin?Bitcoin simply explained: what lies behind the network and the unit BTC, which properties define Bitcoin and why nobody sets the rules on their own.
- Stage 1 · Step 1Bitcoin in 10 minutesWhat Bitcoin is, how it works, why people use it and which risks you should know about – explained concisely and with sources.
- Stage 1 · Step 3How does Bitcoin work?Blockchain, transactions, nodes, miners and consensus: how Bitcoin’s building blocks fit together – with a payment’s journey, step by step.
More from „Basics“
Sources4 sources · 3 publishers
The superscript numbers in the text refer to these sources.
- Bitcoin: A Peer-to-Peer Electronic Cash System – Satoshi Nakamoto, 31.10.2008 (accessed 28/09/2026)
- Genesis block – Bitcoin Wiki (accessed 28/09/2026)
- Controlled supply – Bitcoin Wiki (accessed 28/09/2026)
- Bitcoin Core source code: src/consensus/amount.h (COIN) – Bitcoin Core (GitHub) (accessed 28/09/2026)
This entry is for education only and is not investment, tax or legal advice.