What is the difference between Bitcoin and bitcoin?

Bitcoin (capital B) refers to the decentralised network and protocol. bitcoin (lowercase b) refers to the units of currency on that network — the asset you can hold and transfer.

How does a Bitcoin wallet work?

A Bitcoin wallet holds your private keys — cryptographic proof that you control certain bitcoin on the network. The wallet doesn't store coins; it stores the keys that unlock them on the blockchain.

Why is 21 million the maximum Bitcoin supply?

Satoshi Nakamoto hardcoded 21 million as the supply cap. This fixed supply makes bitcoin deflationary by design — unlike fiat currencies, no central authority can issue more.

What is the Bitcoin blockchain?

The blockchain is a public ledger of every Bitcoin transaction ever made. Each block contains a batch of transactions cryptographically linked to the previous block, making the history tamper-proof.

Bitcoin the Network&bitcoin the Coin

Two things. One system. Understanding the difference is the first step to understanding everything.

Why the Capital Letter Matters

This is not a typo. The capital B and lowercase b mean two different things.

Bitcoin

The Network

Capital B refers to the protocol, the network, and the system as a whole. The decentralized infrastructure that no one owns and everyone can use.

Ownership: Nobody owns the network. Everyone can use it.

"The Bitcoin network processed 500,000 transactions today"

"Bitcoin has never been hacked"

"Bitcoin runs on thousands of nodes worldwide"

bitcoin

The Coin

Lowercase b refers to the unit of value, the currency, the asset. The thing you buy, hold, send, and receive.

Ownership: Only you own your coins. Your keys, your bitcoin.

What about "BTC"? — BTC is the ticker symbol used on exchanges, the same way USD is the ticker for the US dollar. It's just shorthand for bitcoin — the coin, lowercase b.

"She bought 0.1 bitcoin last month"

"His bitcoin is stored in a hardware wallet"

"The price of bitcoin reached a new high"

The Connection

Bitcoin the network creates, secures, and transfers bitcoin the coin. The network has no value without the coin to incentivize participants. The coin has no security without the network to validate it. They need each other — but they are not the same thing.

Why is BTC all caps? — BTC is a ticker symbol, just like USD means the US dollar. Ticker symbols are always written in capitals — it's a financial convention, not a statement about the network. So BTC doesn't follow the B vs b rule. It simply refers to bitcoin the coin, written the way markets write it.