A Bitcoin & Ethereum address validator checks whether a cryptocurrency address conforms to the format rules for its type. Bitcoin has three address types (Legacy P2PKH, SegWit P2SH, and native SegWit Bech32) with different encoding schemes. Ethereum addresses are 42-character hex strings with an optional EIP-55 checksum. Validating before sending funds prevents costly send-to-wrong-address errors.
Validation Checks
Address Details
Address Type Reference
Original Bitcoin address format. 25-34 characters. Uses Base58Check encoding (digits 1-9, A-Z, a-z, excluding 0, O, I, l).
Pay-to-Script-Hash addresses. Compatible with older wallets while supporting SegWit. 25-34 characters. Base58Check encoded.
Native SegWit (BIP 84/141). Lower transaction fees. 42-62 characters. Bech32 encoded (digits 0-9, lowercase a-z, excluding b, i, o, 1).
Ethereum mainnet address. Exactly 42 characters: 0x + 40 hex digits. Optional EIP-55 mixed-case checksum. Also used for ERC-20 tokens.
How to Validate a Bitcoin or Ethereum Address
Cryptocurrency addresses are case-sensitive identifiers used to receive funds on a blockchain. Unlike bank account numbers, a crypto transaction to the wrong address is irreversible — there is no bank to contact for a reversal. Validating an address before sending funds is a critical safety step.
Identifying the Address Type
The first characters of a crypto address identify its type. Bitcoin Legacy addresses start with "1" (example: 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2). P2SH addresses start with "3". Native SegWit (Bech32) addresses start with "bc1" and are always lowercase. Ethereum addresses start with "0x" followed by exactly 40 hex characters.
What This Tool Validates
For Bitcoin addresses (Legacy and P2SH), the tool checks: valid Base58 character set (no 0, O, I, or l), correct length (25-34 characters), and valid prefix. For Bech32 addresses, it validates: correct "bc1" prefix, Bech32 character set compliance (no b, i, o, 1 in the data part), and length (42-62 characters). For Ethereum addresses, it validates: correct "0x" prefix, exactly 40 hexadecimal characters, and optionally validates the EIP-55 mixed-case checksum.
Common Address Errors
The most common errors are: missing characters from a copy-paste operation, accidentally copying the surrounding whitespace but missing the last few characters, and confusing testnet addresses with mainnet addresses. Bitcoin testnet addresses start with 'm', 'n', or 'tb1' — these will fail validation in this tool which checks for mainnet addresses only. Ethereum addresses with incorrect capitalization (not following EIP-55 checksum) are still technically valid — the EIP-55 checksum is optional.
FAQ
What types of Bitcoin addresses are there?
Bitcoin has three main address formats. Legacy (P2PKH) addresses start with '1' and are 25-34 characters long using Base58 encoding. P2SH (SegWit wrapped) addresses start with '3' and are also 25-34 characters in Base58. Native SegWit (Bech32) addresses start with 'bc1' and are 42-62 characters using Bech32 encoding with lowercase letters and specific character restrictions.
How do I validate an Ethereum address?
An Ethereum address is always 42 characters: '0x' prefix followed by 40 hexadecimal characters (0-9 and a-f). The optional EIP-55 checksum uses mixed case (capital letters for specific positions) to provide error detection, but lowercase-only addresses are also valid. This tool validates both checksummed and non-checksummed formats.
Does this tool verify if a crypto address actually exists or has funds?
No. This tool validates FORMAT only — it checks the structural rules (correct prefix, valid character set, correct length) but cannot verify if an address is active, has ever received funds, or is associated with any account. To check an address's balance or transaction history, use a blockchain explorer like blockchain.info (Bitcoin) or etherscan.io (Ethereum).
What is Base58 encoding?
Base58 is an encoding scheme used for Bitcoin Legacy and P2SH addresses. It uses 58 characters (digits 1-9 and letters A-Z plus a-z, excluding 0, O, I, and l to avoid visual confusion). Bitcoin Legacy addresses must contain only these 58 characters. Bech32 addresses use a different character set: only digits 0-9 and lowercase letters a-z, minus the characters b, i, o, and 1.
Why is my valid-looking address marked invalid?
Common reasons: (1) Testnet addresses — Bitcoin testnet addresses start with 'm' or 'n' (Legacy) or 'tb1' (Bech32), not '1' or 'bc1'; (2) Copied incorrectly — missing or extra characters; (3) Uppercase Bech32 — native SegWit addresses must be all lowercase (bc1...); (4) Wrong chain — an Ethereum address starting with 0x won't validate as Bitcoin.
Is this tool free?
Yes, completely free with no signup required. All address validation runs locally in your browser — no address data is sent to any server.