What is a Bitcoin Address?
A string of letters and numbers that represents a destination for a Bitcoin payment. Similar to an email address, but for receiving bitcoin. Bitcoin addresses are derived from public keys and typically start with '1', '3', or 'bc1'.
Why It Matters
Addresses are your entry point into receiving payments. Need to receive bitcoin? You share an address. Just like email: you give someone your address, they send something to it.
What's good about Bitcoin addresses: they're public information. You can safely share them with anyone. Unlike a bank account number, which reveals identifying information, a Bitcoin address is a random-looking string that doesn't tie to your identity by default. Understanding addresses matters because sending bitcoin to the wrong address means your funds are gone forever. No undo button. Bitcoin transactions are immutable, and a single typo in an address can vaporize a transfer with no recourse from any exchange, wallet provider, or court.
How It Works
Your wallet generates Bitcoin addresses from your public key using cryptographic hashing. Three formats you'll encounter. Legacy addresses start with 1. The original format. P2SH addresses start with 3 and offer additional flexibility for things like multisig. Bech32 addresses start with bc1 and are the newest standard, with lower transaction fees as a built-in benefit.
Your wallet can generate unlimited addresses from a single seed phrase. Each address can receive payments independently. When someone sends you bitcoin to one of your addresses, the transaction broadcasts to the network and eventually gets confirmed into a block, which is the point at which the transfer becomes part of Bitcoin's permanent record and no longer reversible by anyone in the world.
Real-world examples. A legacy address looks like "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa," the address Satoshi used in the Genesis Block. It has received over 100 BTC in tributes from anonymous senders over the years. A P2SH address starts with 3, like "3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy." A bech32 SegWit address starts with bc1, like "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4." Most wallets default to bech32 now because of the lower transaction fees and better error detection it provides.