What is Base58 and what is it used for?

Base58 encodes binary data with 58 characters and is best known from Bitcoin, where it underpins addresses, WIF private keys and other identifiers that people copy or read by hand.

Why does Base58 drop some characters?

Base58 omits 0 (zero), O (capital o), I (capital i) and l (lowercase L) because they are easy to confuse visually. This is why it is used where a single mistyped character would be costly.

How does Base58 encoding actually work?

The input bytes are treated as one big number and repeatedly divided by 58; each remainder maps to an alphabet character. Unlike Base32 or Base64, it is not block-based, so it has no padding.

How are leading zero bytes handled?

Each leading zero byte in the input is encoded as a leading 1 character, matching the Bitcoin Base58 convention. The decoder restores those zero bytes exactly.

Is this the same as Base58Check?

No. This tool does plain Base58 encoding and decoding. Base58Check adds a version byte and a 4-byte checksum on top of Base58, which this tool does not compute.

Why is Base58 not padded like Base64?

Because Base58 works on the whole number rather than fixed bit blocks, there are no leftover bits to pad. Leading zero bytes are the only special case, and they become leading 1s.

No — all encoding and decoding happens in your browser with no network requests.

Base58 Encoder & Decoder

Base58 encoder and decoder (Bitcoin alphabet)

Base58 encodes binary data using 58 characters, deliberately leaving out the visually ambiguous 0, O, I and l. This makes encoded values safer to read, copy and type by hand, which is why it underpins Bitcoin addresses, WIF private keys and other crypto identifiers.

How it works

To encode, the tool converts your text to UTF-8 bytes and treats the whole byte array as a single large number. It repeatedly divides that number by 58, collecting each remainder, and maps the remainders to the alphabet 123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz. Any leading zero bytes in the input are emitted as leading 1 characters. Decoding reverses the process — multiplying by 58 and adding each digit’s value — to rebuild the original bytes, then decoding them as UTF-8.

Example

Encoding the text Gera:

Gera → bytes 47 65 72 61 → 2prCMN

Input	Base58
`Hi`	`6Wc`
`Gera`	`2prCMN`

This is plain Base58 (no checksum), and everything runs locally in your browser.