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About this tool
Encode text to Base58 (Bitcoin alphabet) or decode it back.
The Base58 Encoder converts ordinary UTF-8 text to and from raw Base58 using the Bitcoin alphabet. It treats the UTF-8 bytes as one big integer and repeatedly divides with BigInt so long values stay exact. The alphabet is 123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz; 0, O, I and l are omitted to reduce visual ambiguity. This is raw Base58, not Base58Check, WIF, encryption, or a wallet-key recovery tool.
Open Base58 Encoder on AltFTool — it loads instantly in your browser.
Type or paste your text into the 'Input' box — or click the 'Encode Hello' chip in the 'Examples' row to load a sample — then set 'Mode' to 'Encode to Base58' or 'Decode from Base58'.
The 'Result' panel updates live as you type; there is no submit button. Encoding converts the text to UTF-8 bytes and shows accurate 'Input bytes' and 'Output chars' counts, while decoding validates the Base58 characters and recovers UTF-8 text.
Use 'Copy' or 'Download' to keep the result — Download saves base58-encoder.txt containing the tool title, your Input and Mode, and the Result — or 'Reset' to put the Input back to its default 'Hello'.
The base conversion runs on BigInt, so long inputs convert exactly instead of losing precision past 2^53.
Flip the mode select to decode the same box you just encoded from. Invalid alphabet characters and byte sequences that are not valid UTF-8 are rejected instead of silently altered.
Each leading zero byte in the input becomes a leading 1 in the output and is restored on decode, which is the rule that keeps Base58 addresses stable.
Four: the digit 0, the capital letter O, the capital letter I, and the lowercase letter l. Removing them leaves 58 symbols that cannot be confused with each other when a value is read aloud or copied by hand.
Base58 drops the four ambiguous characters and both non-alphanumeric symbols (+ and /), and uses no padding, so a value can be double-clicked, typed, or written down safely. The trade-off is size: Base58 output is longer than Base64 for the same data.
Because the input began with a zero byte. Base58 encodes the value as a number, which would otherwise lose those leading zeros, so each one is written back as a literal 1 character at the front.
It uses the same alphabet, but a Bitcoin address is Base58Check — a version byte plus a 4-byte double-SHA-256 checksum appended before encoding. This tool does the raw Base58 conversion only, so it will not validate or generate a checksummed address.