Base58 decoder.

Base58 is Bitcoin's alphabet, written by Satoshi Nakamoto in 2009: the 62 letters and digits without the four that look alike, 0 (zero), O (capital o), I (capital i) and l (lowercase L). It exists so that an address copied by hand, or read from a screen, is not mistyped. The tool treats the input bytes as one big number and writes it.

The bytes are read as one integer, big end first, and written in base 58 by repeated division; each leading zero byte becomes a leading 1, the alphabet's zero digit. Each character carries about 5.86 bits, so the output is about 37% larger than the input. There is no padding.

Bitcoin addresses and private keys (as Base58Check, which adds a version byte and a four-byte checksum), IPFS content ids that start with Qm, Solana account keys, Monero and Ripple addresses (Ripple with its own alphabet order), and short ids where people copy by hand.

It gives up a little density (37% against Base64's 33%) and a lot of speed (the whole input is one number) for strings a person can transcribe without error. Use it where people read and type the value; use Base64 where only machines do.

Probably a different alphabet or a checksum. Bitcoin's order (1 to 9, A to Z, a to z, minus the look-alikes) is the one here, and Flickr and Ripple reorder it. A Bitcoin address is Base58Check: the tool decodes it to its raw bytes, including the version byte and the four-byte checksum at the end, and doesn't verify the checksum.

No. Base58 is an encoding, not encryption: it changes how bytes are written, not who can read them, and anyone can decode it with no key. Encrypt first (AES, age, a library's sealed box) when the content needs protecting, then encode the ciphertext if it has to travel as text.

Paste the Base58 and the text appears as you type; the status line says how many characters became how many bytes. Spaces and line breaks are ignored, so a wrapped value from an email or a config file pastes as it is. Press Swap to encode the result again.

The decoder gives you the bytes as UTF-8 text when they are text. When they aren't, an image or a PDF for instance, it still shows them, with replacement characters where the bytes aren't valid UTF-8, and the status line says so. Use Base58 to file to download the bytes as they are instead.

Base58 uses 1 to 9, A to Z and a to z, without 0, O, I and l, and the error names the first character that isn't among them. Check for a stray quote, a trailing comma or a prefix from the surrounding code. Spaces and line breaks are dropped for you.

Nothing leaves your browser. The text is read into memory on your machine and the encoding is computed there, in plain JavaScript; the page makes no request with it. Load the page, go offline and it keeps working.

No. The Base58 decoder is free and opens without a sign-in, an account or an install.

Nothing. The Base58 decoder holds your input in the page's memory, so closing or reloading the tab clears it, and it saves nothing in this browser.

It takes Bitcoin's alphabet, which leaves out 0, O, I and l, and reads a leading 1 as a zero byte. Anything else stops with a message naming the first character it can't read.

Yes: drop a text file that holds the Base58 on the input. The file is read as text and decoded, so a saved encoding doesn't need pasting.

Press Swap once there is a result and the same tool becomes the Base58 encoder, with the decoded text moved into the input.

Closest to the Base58 decoder: Base58 encoder, Base58 to file, File to Base58, Base62 decoder. Each opens on its own page, free and in the browser.

The Base58 decoder is one of 32 in its group. The group's page, /tools/encoding, lists them all.

The tool is free. Its interface is built from shadcn.io's own components (Button, Input, Slider and the rest of the registry under /ui), which come in React, Vue, Svelte and Solid. Pro adds the blocks and templates for the product around it.