What is Bitcoin?
The first cryptocurrency — a decentralised digital currency with a fixed supply of 21 million, running since 2009.
Bitcoin is the original cryptocurrency, launched in 2009 by the pseudonymous Satoshi Nakamoto, and it remains the reference point for the entire asset class. Its design is deliberately narrow: digital money with a fixed maximum supply of 21 million coins, issued on a schedule that halves roughly every four years, secured by a global network of miners. No company, no CEO, no ability for anyone to print more.
That scarcity-by-code is the core of the investment thesis — supporters treat it as a digital counterpart to gold, and its halving cycle has historically shaped the whole crypto market's rhythm. Critics point at its volatility and energy use. Both camps have a decade of data to argue from, and the honest position is that Bitcoin has survived every obituary written for it while still moving in price like a risk asset rather than a stable store of value.
In Australia, Bitcoin is legal to buy on AUSTRAC-registered exchanges, taxed as a CGT asset, and now also accessible through Australian-listed ETFs for people who'd rather not hold it directly.
See it in practice
Related terms: Blockchain · Halving · Market cap · full glossary
FAQ
Who controls Bitcoin?
Nobody, in the sense that matters: the rules are enforced by thousands of independent computers, and changing them requires broad agreement across the network. Developers propose, miners and node operators dispose.
Why does the 21 million cap matter?
It makes Bitcoin the first money whose total supply is fixed by code rather than policy. Whether that scarcity deserves a monetary premium is the entire Bitcoin debate in one sentence.
General information only, not financial advice. Definitions are maintained in our fact database and reviewed with the daily rebuild.