Bitcoin is digital money that people can send directly over the internet without asking a bank to process the payment. It is also the name of the open network that records and verifies those payments.
This guide explains the essential ideas without assuming that you already understand cryptography, mining, or financial markets.
Bitcoin is both money and a network
When people say Bitcoin, they may mean the network, the rules followed by that network, or the asset transferred through it. The asset is commonly written as bitcoin with a lowercase b.
No single company owns the network. Instead, independently operated computers called nodes check transactions and blocks against the same shared rules. A transaction that breaks those rules is rejected even if someone powerful wants it accepted.
You can explore the shorter definitions in the BTCFQ Bitcoin glossary whenever a term is unfamiliar.
How a Bitcoin payment works
A wallet prepares a transaction that identifies existing bitcoin outputs to spend and creates new outputs for the recipient. The wallet signs the transaction with private-key information, then broadcasts it to the network.
Nodes verify that the transaction follows Bitcoin's rules. Miners select valid transactions and compete to add a new block. When a transaction appears in a block, it receives its first confirmation. Each later block adds another confirmation.
The public blockchain records this transaction history. It does not work like a bank account ledger with one editable balance. Wallet balances are calculated from unspent transaction outputs, often shortened to UTXOs.
Why Bitcoin mining exists
Mining makes adding blocks costly and competitive. Miners repeatedly perform proof-of-work calculations. A miner that finds a valid result can propose a block, and nodes independently verify both the block and its proof of work.
This process orders transactions and makes old history increasingly difficult to change. Miners cannot simply invent valid coins or rewrite rules: nodes reject blocks that violate the supply schedule or other consensus rules.
Why Bitcoin has a limited supply
Bitcoin's issuance rules reduce the amount of new bitcoin created over time and cap the total supply at 21 million bitcoin. The scheduled reduction is called the halving.
The limit is enforced in software by validating nodes. Changing a number in one miner's software would not force other nodes to accept invalid blocks.
How people hold bitcoin
A Bitcoin wallet manages the keys needed to receive and spend bitcoin. The coins are not stored inside the phone or hardware device. The blockchain records the spendable outputs, while the wallet manages the information needed to authorize transactions.
With a custodial service, another organization controls the keys. With a non-custodial wallet, you control them and take responsibility for backups. Neither approach removes risk, so beginners should understand the tradeoff before moving funds.
What Bitcoin does not guarantee
Bitcoin does not guarantee profit, stable prices, reversible payments, or recovery when keys are lost. Transactions can be publicly analyzed, and mistakes may be permanent. Educational information should not be treated as personalized financial, legal, or tax advice.
Start with small, low-risk learning steps. Read the BTCFQ frequently asked questions, learn how wallets and backups work, and verify every address before sending.
