What is Base58 and why does Bitcoin use it?

Base58 is a binary-to-text encoding that uses 58 characters — the digits and letters minus the four that look alike (zero, capital O, capital I and lowercase l) plus the plus and slash that Base64 uses. Bitcoin adopted it so addresses and keys can be copied, typed and read aloud with far less chance of a transcription error.

What is the difference between Base58 and Base58Check?

Plain Base58 just re-encodes the bytes. Base58Check first appends a 4-byte checksum (the first four bytes of a double SHA-256 of the payload) before encoding. On decode the checksum is recomputed and compared, so a single mistyped character is caught instead of silently producing the wrong address.

How does Base58 handle leading zero bytes?

Because Base58 treats the input as one big number, leading zero bytes would otherwise vanish. The standard fixes this by emitting one leading "1" character (value 0 in the alphabet) for every leading 0x00 byte, then encoding the remaining big integer. This decoder reverses that exactly so byte-for-byte round-trips hold.

Can I encode raw hex instead of text?

Yes. Switch the input format to "Hex bytes" when encoding. This is what you want for public-key hashes, private keys or any binary payload, since typing them as text would corrupt the bytes. Spaces and an optional 0x prefix are ignored.

Why does my decoded Base58 show as hex instead of text?

Many Base58 strings (like addresses) are not UTF-8 text — they are raw bytes. When the bytes are not valid UTF-8 the tool shows the exact byte sequence as hex so you can still inspect or copy it without garbled characters.

Is my data sent anywhere?

No. All encoding, decoding and SHA-256 checksum work happens locally in your browser using the built-in Web Crypto API. No keys, addresses or text ever leave your device.

Base58 Encoder / Decoder

A complete Base58 and Base58Check encoder / decoder that runs entirely in your browser. Base58 is the binary-to-text encoding behind Bitcoin addresses, WIF private keys, IPFS content IDs and many short-link schemes. It keeps data compact like Base64 but throws away the characters that trip humans up — so the result is safe to read aloud, type by hand and double-click to select. This tool converts text or raw hex into Base58, decodes Base58 back to bytes, and can append or verify the 4-byte checksum that makes a string self-validating.

How it works

Base58 treats your input bytes as a single big-endian arbitrary-precision integer and repeatedly divides by 58, mapping each remainder to one of the 58 alphabet characters: the digits 1-9 and the letters, minus 0, O, I and l. Because the whole input is one number, naive encoding would silently drop leading zero bytes — so the standard prepends one 1 for every leading 0x00 byte and encodes the rest. This tool uses JavaScript BigInt, so it stays exact no matter how long the input is, and it preserves leading zeros in both directions.

Enable Base58Check and the encoder first appends a 4-byte checksum — the first four bytes of SHA-256(SHA-256(payload)), computed with the browser’s Web Crypto API — before encoding. On decode it recomputes that checksum and compares: a mismatch means the string was mistyped or corrupted, and the tool tells you the expected versus actual bytes. You can encode from UTF-8 text or raw hex, and every result shows the underlying bytes in hex with its own copy button.

Example

Encoding the text Gera Tools (10 bytes) gives the Base58 string 8Vw9jWiZ4xN5kT (illustrative). Encoding the hex payload 00 00 5a 1b keeps both leading zero bytes as two leading 1 characters in the output, proving the leading-zero rule. With Base58Check on, the same payload is extended by a 4-byte checksum first, so the encoded string is a few characters longer and any later typo is caught on decode.

Task	Input	Mode
Encode text	`hello`	Encode · Text
Encode key bytes	`1a2b3c…`	Encode · Hex
Verify an address-style string	a Base58 string	Decode · Base58Check

Every byte is computed locally — no addresses, keys or text are ever uploaded.