Base64 Encode/Decode

About the base64 encode / decode

Encode text to Base64 or decode Base64 back to readable text. Handy for HTTP Basic auth headers, data URIs, email bodies and config values that must be ASCII-safe. It handles Unicode correctly by encoding as UTF-8 first.

How to use it

1. Choose Encode or Decode at the top.
2. Paste your plain text or Base64 string into the input box.
3. Click Encode to Base64 or Decode from Base64.
4. Copy the output, or use the swap button to feed the result back in the other direction.

Questions

Is Base64 encryption?

No. Base64 is an encoding that anyone can reverse instantly, with no key. Never use it to hide passwords or secrets.

Why does Base64 make data bigger?

It represents every 3 bytes as 4 ASCII characters, so output is about 33% larger than the input, plus padding.

What does the = at the end of a Base64 string mean?

It is padding, added when the input length is not a multiple of 3 bytes. One or two = signs are normal.

Why do I get "Invalid Base64 string" when decoding?

The input contains characters outside the Base64 alphabet or has the wrong length. URL-safe Base64 (with - and _ instead of + and /), as used in JWTs, must be converted to standard Base64 first.