Address tools

Check a Bitcoin address

Check whether a Bitcoin address is valid, detect its type and, if you want, see its balance and activity. The validity check runs locally in your browser; we only look up the balance server-side when you click.

Your browser computes validity and type; the address does not leave your device for that. Only "Check balance" sends it to our server, which queries mempool.space. Your IP is not shared with third parties.

Why validate an address?

Before sending Bitcoin, a validity check pays off. Every Bitcoin address carries a built-in checksum. If you mistype, the tool spots it immediately, so you avoid sending to a broken or wrong address. It is no substitute for care, though: a formally valid address can still be the wrong one.

The address types

  • 1… Legacy (P2PKH): the oldest format.
  • 3… P2SH: script addresses, often nested SegWit or multisig.
  • bc1q… Native SegWit (bech32, P2WPKH/P2WSH): lower fees.
  • bc1p… Taproot (bech32m, P2TR): the newest format.

The tool recognises testnet addresses too. It only shows a balance for mainnet addresses.

Why is the balance public?

Bitcoin is an open ledger: every transaction and every address balance is recorded in the blockchain forever and readable by anyone. The system rests on that openness: it lets anyone independently verify that no bitcoin is created out of thin air. For privacy, though, it means that whoever links an address to an identity can trace its entire history.

Privacy: the validity check is purely computational and runs entirely in your browser. For the balance we query mempool.space server-side so your IP is not sent to the data provider, and we do not permanently store the addresses you look up.

Frequently asked questions

01What does this tool check?

It checks whether a Bitcoin address is formally valid: whether the checksum matches and the format is known. It also determines the address type (Legacy, P2SH, SegWit, Taproot) and the network. On request it shows, for mainnet addresses, the current balance (including unconfirmed mempool transactions), the total received and sent amounts and the number of transactions, in BTC and the selected fiat equivalent.

02Does my address leave the browser?

Not for the validity check: the Base58Check and Bech32 computation runs entirely locally in your browser. Only when you click "Check balance" does the address go to our server, which queries mempool.space. The data provider therefore only sees our server, not your IP or the address you looked up tied to you.

03Why is an address invalid?

Usually a typo: one wrong or swapped character breaks the checksum and the address is rejected. Always copy addresses instead of typing them.

04Does this show my "wallet balance"?

Only for the single address you look up. Modern wallets use many addresses; your total balance is usually spread across several. For a full picture you would need all of the wallet's addresses (or the xpub).

05Why does the balance differ slightly?

Unconfirmed mempool transactions change the balance until they land in a block. The tool tells you when the balance shown includes unconfirmed transactions. We also keep a result for up to 60 seconds.