Bitcoin is the first and largest cryptocurrency — decentralized digital money that runs on a public blockchain, with no bank or government in control and a supply capped at 21 million coins. This guide explains what it is and why it matters.
A new kind of money
Bitcoin launched in 2009, created by the pseudonymous Satoshi Nakamoto as "peer-to-peer electronic cash." It lets people send value over the internet directly, without a bank or payment processor in the middle. Transactions are recorded on a public ledger — the blockchain — that anyone can verify and no single party controls [1].
Why 21 million
Bitcoin's supply is capped at 21 million coins, written into its protocol. New bitcoin enters circulation through mining, and roughly every four years a "halving" cuts the block reward in half, slowing issuance until the last coin is mined around 2140 [1][2]. This fixed, predictable scarcity is central to Bitcoin's "digital gold" narrative.
Bitcoin at a glance
How it stays secure
Bitcoin uses Proof of Work: miners compete to validate transactions and add blocks, making the ledger extremely costly to rewrite (see our mining and Proof of Work vs Proof of Stake guides). Ownership is controlled by private keys — lose them and the coins are gone (see our seed-phrase guide).
The bottom line
Bitcoin is decentralized, capped-supply digital money secured by a global network — the asset that started the entire crypto market. Understanding it is the foundation for everything else. To keep learning the fundamentals, follow more from Bitbase Academy.
Disclaimer: This article is educational content from Bitbase Academy, provided for information only. It does not constitute investment, trading, tax, or financial advice. Crypto assets are volatile; assess your own risk. Written as of June 2026; refer to the latest official information.
References
[1] River, "Can Bitcoin's hard cap of 21 million be changed?" river.com
[2] CCN, "How Does the Bitcoin Source Code Define Its 21 Million Cap?" ccn.com
