Base converter

Encode and decode between text and Base2 through Base85, or convert integers between any two bases.

Runs entirely in your browser. Nothing you enter here is sent to the server.

This tool needs JavaScript

It does its work in your browser, which is exactly why it cannot fall back to the server: that would mean sending your input somewhere. With scripting off there is nothing for it to run on.

From

Input

Output

From base

To base

Number

Result

Whole numbers of any size, negatives included. Digits above 9 are letters a–z, so base 36 is the top.

What each encoding is, and the conventions used here

The top half converts bytes. Your input is decoded from the format on the left into raw bytes, then re-encoded into the format on the right. "Text" means UTF-8. Everything happens in this page.

Text: UTF-8. One emoji is four bytes, not one character.
Base2, Base8: One group per byte — eight binary digits or three octal digits — separated by spaces. This is the byte-by-byte reading, not one huge number, so leading zero bytes survive. Spaces are optional on the way in.
Base16: Hex, lowercase out, either case in. Whitespace and 0x ignored.
Base32: RFC 4648: A–Z and 2–7, padded with =. The same alphabet TOTP secrets use.
Base36, Base58: Positional: the whole input is treated as one big number. Base58 is the Bitcoin alphabet, which drops 0, O, I and l so nobody mistypes them. Leading zero bytes are preserved as leading 1s, the way Base58Check does it.
Base64: RFC 4648 standard, with + and / and = padding.
Base64url: Same, but - and _ so it survives being put in a URL. Padding is dropped on output and accepted on input.
Base85: Ascii85 as used by PostScript and PDF, without the <~ ~> wrapper. Four bytes become five characters, so it is about 7% smaller than Base64.

Decoding is strict: a character that does not belong is reported with the position it was found at, rather than being skipped to produce plausible nonsense.

None of this is encryption

Base64 and friends are for moving bytes through channels that only accept text. Anything encoded here can be decoded by anyone, instantly, with no key. If it needs to stay secret, it needs encryption.

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