Base64 Encoder and Decoder

How to use it

1. 1Paste your text into the box marked "Text to encode"Paste the text you want encoded, or the Base64 you want back. The Encode and Decode buttons switch direction, and the input label changes with them. Everything happens inside your browser — nothing is uploaded, so there is nothing for us to store, log or lose.
2. 2Read the result as it updatesThere is no button to press. The conversion happens as you type. The output recomputes every time you change the text or one of the options above it.
3. 3Turn on URL-safe if it is going in a URLIt swaps + and / for - and _, which are the characters that break when Base64 is put in a query string or a path. This is the cause of most "it works locally" token bugs.
4. 4Use Wrap at 76 for email and PEMSome older formats require lines no longer than 76 characters. Nothing on the web does, so leave it off unless you know you need it.
5. 5Expect emoji and non-Latin text to surviveEncoding is UTF-8 throughout in both directions, which is where naive implementations mangle anything outside plain ASCII.
6. 6Copy or download the resultThe buttons under the output put it on your clipboard or save it as a file, and each one says exactly what it will copy or download. Any note about something the tool changed or deliberately left alone is shown with the result rather than hidden.

About this tool

Base64 rewrites arbitrary bytes using 64 characters that survive being sent through systems built for text — email bodies, JSON strings, data URIs, HTTP headers. It is an encoding, not encryption: anyone can decode it, and it makes data about a third larger.

The reason to use this tool rather than the first result on a search is that most Base64 tools quietly corrupt anything outside ASCII. The browser functions underneath, `btoa` and `atob`, only accept characters up to code 255, so an emoji or a Tamil character either throws an error or comes back mangled. This tool encodes through UTF-8, so the round trip is exact for any text you can type.

Understanding the result

Encoding turns your text into the Base64 alphabet: A–Z, a–z, 0–9, "+" and "/", padded to a multiple of four with "=".

The URL-safe option uses "-" and "_" in place of "+" and "/" and drops the padding. This is what JWTs and URL parameters use, and feeding one variant to something expecting the other is a common and confusing failure.

Decoding tells you when the result is not text at all. Bytes that are not valid UTF-8 mean you have decoded binary — an image or an archive — rather than something that can be displayed.

Example

Roftr Clouds · ரோஃப்டர்

Um9mdHIgQ2xvdWRzIMK3IOCusOCvi+CumuKAjeCuquCvjeCun+CusOCvjQ==

Limitations

• Base64 provides no confidentiality whatsoever. Anything encoded can be read by anyone who sees it; do not use it to hide a password or a key.
• Encoded output is about 33% larger than the input. That matters when the result goes into a URL or a database column with a length limit.
• Very large inputs are bounded by your browser's memory. Several megabytes is comfortable; a hundred is not.
• Decoding cannot tell you what the original data was. A decoded string that looks like nonsense may be correctly decoded binary rather than a mistake.

Questions