What is the difference between Bech32 and Bech32m?

Bech32 is the original SegWit address encoding used for witness version 0 (P2WPKH and P2WSH, the bc1q addresses). Bech32m is a modified checksum introduced in BIP-350 for witness version 1 and later, which Taproot (bc1p) uses. They use different checksum constants, so a v1 address must use Bech32m to be valid.

Does a valid checksum mean the address holds funds?

No. The checksum only proves the address is correctly formed and was not corrupted in transit. It says nothing about whether the address has a balance or who controls the keys. Always send a small test transaction to a new address first.

How does the legacy checksum work?

Legacy addresses use Base58Check: the version byte plus the hash160 payload are hashed twice with SHA-256, and the first four bytes of that hash are appended as a checksum. The validator decodes the Base58 string, recomputes the double SHA-256, and compares the last four bytes.

Why is a mixed-case Bech32 address rejected?

BIP-173 forbids mixing upper and lower case in a Bech32 address because the checksum is only defined for a single case. Wallets always emit all-lowercase Bech32 addresses, so a mixed-case string is a sign of a copy error and is correctly flagged invalid.

Can it validate testnet addresses?

Yes. Testnet legacy addresses start with m, n, or 2, and testnet Bech32 addresses use the tb1 prefix. The tool detects the version byte or human-readable part and labels them as testnet rather than mainnet.

Bitcoin Address Format Validator

A single mistyped character in a Bitcoin address does not bounce — funds sent to a malformed or wrong address are gone forever. This validator catches transcription errors before you broadcast by recomputing the address checksum locally, so you can confirm a deposit address is well-formed without trusting a remote service.

How it works

Bitcoin uses two checksum schemes depending on the address era. Legacy addresses (those starting with 1 or 3) are Base58Check encoded: a version byte and the 20-byte public-key or script hash are concatenated, hashed twice with SHA-256, and the first four bytes of that digest are appended as a checksum. To validate, the tool Base58-decodes the string, splits off the trailing four bytes, recomputes the double SHA-256 over the payload, and checks that the four bytes match.

SegWit addresses (starting with bc1) use Bech32 or Bech32m. The string is split at the last 1 into a human-readable part (bc) and a data part encoded in a 32-symbol alphabet. A polynomial checksum over the expanded HRP and data must equal a constant: 1 for Bech32 (witness version 0) or 0x2bc830a3 for Bech32m (witness version 1+, i.e. Taproot). The witness version is the first data symbol, so the tool also enforces that v0 uses Bech32 and v1 uses Bech32m, per BIP-350.

Example and notes

Paste bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq and you will see “Native SegWit” with a valid Bech32 checksum. Change one character and the checksum fails immediately. A Taproot address like bc1p... is labelled v1 and validated with Bech32m. Because the algorithm only proves structural integrity, treat a pass as “safe to copy” — not as proof of ownership or balance. Nothing you paste leaves the browser.