What is address?

A unique string of characters that identifies where cryptocurrency can be sent on a blockchain.

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A unique string of characters that identifies where cryptocurrency can be sent on a blockchain.

Addresses are derived from a public key and are safe to share. Sending to the wrong address, or to an address on the wrong chain, usually means permanent loss.

An address is closer to an account number than to an email address. It is public, it is permanent, and there is no directory service, no undo, and nobody to call. Every chain has its own format, and formats that look similar are not interchangeable.

How it works

A wallet generates a private key, derives a public key from it, and derives an address from that. The derivation runs one way, so an address reveals nothing useful about the key behind it.

Formats differ by chain. Bitcoin addresses starting bc1 are native SegWit addresses defined by BIP-173, and BIP-350 later specified the bech32m encoding used for Taproot outputs. These encodings include a checksum, which is why a Bitcoin wallet rejects a mistyped address instead of sending into nothing.

Ethereum addresses are the last 20 bytes of a hash of the public key, written as 40 hexadecimal characters after 0x. Plain hex has no checksum, so EIP-55 added one by varying the letter case, which is why some wallets warn when the capitalization does not match.

Modern wallets derive many addresses from one seed phrase using the hierarchical scheme in BIP-32 and the path convention in BIP-44. That is why a wallet gives you a fresh receiving address each time while still recovering everything from a single backup.

Some chains route deposits through one shared address plus an identifier, which is what a memo destination tag is for.

Example

Illustrative: you want to send USDC to an exchange. The exchange shows an Ethereum address and, separately, an address for a layer 2 network. Both begin 0x and are 42 characters long, and they are not the same destination. Sending to the Ethereum address from the layer 2 network puts your tokens at an address on a chain where nobody at that exchange holds the key. The address was valid, correctly typed, and still wrong.

Why it matters when you buy

Your first withdrawal from an exchange is the first time an address decides whether you keep your money. Get the network right, save the destination once you have verified it, and send a small test amount before a large one. Which networks a venue supports for a given asset varies, so check the exchange's own withdrawal page and compare withdrawal costs at the fee comparison.

Questions

Is it safe to publish my address?

Yes. An address is a public identifier and cannot be used to spend funds. The trade-off is privacy, because anyone with the address can see its full balance and history on a public chain.

Why does my wallet give me a new address each time?

To make chain analysis harder. Addresses derived from the same seed all belong to you, and the wallet tracks every one it has issued, so the old ones keep working.

Can I recover funds sent to the wrong address?

Only if a person or company controls the destination and chooses to help. If it is an exchange, open a support ticket immediately. If nobody holds the key, the funds are gone.

Guides that use this term

  • Address Poisoning and Clipboard Attacks: How They Work and How to Avoid Them

    Address poisoning and clipboard hijacking both attack the same habit, which is copying a destination address from somewhere convenient instead of from the recipient, and both are defeated by verifying the full address at the moment you send rather than recognizing the first and last few characters.

  • Crypto Estate Planning: Making Sure Your Coins Aren't Lost With You

    Passing on cryptocurrency requires two things that an ordinary will does not provide on its own, a record of what exists and where, and a route by which the person inheriting it can reach the keys, because no court order can recover a seed phrase nobody wrote down.

  • How to Set Up a Hardware Wallet

    Setting up a hardware wallet takes five steps: buy the device new from the manufacturer, initialize it yourself so it generates its own keys, write the recovery phrase on paper offline, set a PIN, and restore the wallet from that written phrase before you move any real money onto it.

  • How to Use a Block Explorer to Check a Transaction

    A block explorer is a public search engine for a blockchain, and you check a transaction by pasting its hash into the search box and reading three fields: the status, the number of confirmations, and the receiving address.

  • What Happens If You Lose Your Seed Phrase

    If you lose the seed phrase for a self-custody wallet and no other copy exists, the funds stay visible on the blockchain and become permanently unspendable, because nobody, including the wallet maker, holds a second copy of the key or any authority to reset it.