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Local format inspection

Check whether a Bitcoin address is valid, and which type it is

Check syntax, checksum, network and address family in your browser. A valid address can still belong to the wrong person or network.

Check address format locally

The checker validates characters, encoding and checksum. It does not query a balance.

Checksum -
Network -
Address family -
Encoding -

Common Bitcoin address families

Typical prefixFamilyEncodingMain point
1…Legacy P2PKHBase58CheckBroad support; larger spend size
3…Script / nested SegWitBase58CheckCan represent several script types
bc1q…Native SegWitBech32Lowercase, checksum and lower weight
bc1p…TaprootBech32mWitness version 1
tb1…TestnetBech32 / Bech32mNot for mainnet bitcoin

A valid checksum is only the first check

Checksum validation can catch many typing and copy errors. It cannot prove that the intended person controls the key, that clipboard malware did not replace the address, or that the selected network is correct.

Confirm through a second channel

For a meaningful payment, compare the full address - or a strong portion of it - using a trusted second channel. Wallet address books and small test payments can reduce some risks, but each has trade-offs.

Learn about Bitcoin wallets and safe storage before moving funds.

What this checker deliberately does not do

  • No balance or transaction-history lookup.
  • No wallet connection or message signing.
  • No ownership claim.
  • No address reuse recommendation.
  • No seed phrase or private-key input - ever.

Privacy matters

Looking up an address on a remote service can reveal interest in it. This validator only checks format and checksum; it does not need chain activity to do that job.

Method and boundary

What the address check proves, and what it cannot

Format validation is useful because it is precise and limited.

01

Local syntax check

The checker reads prefix, character set, payload, witness version, and checksum rules for common Bitcoin address families.

02

No ownership proof

A valid encoding does not identify the recipient, confirm control of a key, inspect a balance, or detect clipboard replacement.

Address checks to complete before sending

Does valid mean safe to pay?

No. Valid means the text follows an address encoding and checksum. It does not prove the intended recipient controls the key or that malware did not replace the address.

Why is a testnet address rejected for mainnet use?

Test networks use different prefixes so valueless test coins are not confused with mainnet bitcoin. Always confirm the wallet's selected network before sending.

Does checking an address expose it?

This page sends the address only to Bitcoin.now's format-validation endpoint and does not query chain history. Never enter a seed phrase or private key into any address checker.

Local format inspection

Check an address before anything depends on it

The checker validates the format and checksum of a Bitcoin address and identifies its type and network. It runs entirely from the string you paste; nothing is looked up, sent or stored.

1

A valid checksum catches typos, not fraud

Legacy addresses use Base58Check with a four-byte checksum; bc1 addresses use Bech32 or Bech32m, which detect any single error and most others. A passing check means the string is well formed - not that the owner is who you think.

  • Compare the first and last several characters against the source you trust.
  • Confirm the network: tb1 and m/n prefixes are testnet.
  • Read the address on a hardware wallet's own screen when you can.
Address formats explained →
2

Type tells you cost and capability

Addresses starting with 1 are legacy, 3 are script hashes often used for multisig or wrapped SegWit, bc1q are native SegWit and bc1p are Taproot. Sending to any of them works; spending from the newer types costs less.

  • Some older services still cannot send to bc1p.
  • A 3-address may hide a multisig behind it.
  • Never send to an address from a screenshot or a chat without verifying it.
How to send bitcoin safely →

What each address type looks like

TypeStarts withEncodingIntroduced
P2PKH (legacy)1Base58Check2009
P2SH3Base58Check2012, BIP 16
P2WPKH / P2WSH (native SegWit)bc1qBech322017, BIP 173
P2TR (Taproot)bc1pBech32m2021, BIP 350