Base64 Encoder & Decoder

What this does

Base64 represents arbitrary bytes using 64 characters that survive being copied through systems built for plain text — which is why it turns up in data URLs, email attachments, HTTP Basic authentication headers and the three parts of a JSON Web Token.

A common bug with Base64 in the browser is that the built-in btoa function only accepts characters in the Latin-1 range, so text containing emoji or scripts such as Devanagari fails. This tool converts your text to UTF-8 bytes first, so any text round-trips correctly.

How to use it

1. Type or paste text and press Encode, or paste Base64 and press Decode.
2. Tick URL-safe to use - and _ instead of + and /, without = padding — the variant used in URLs and in JWTs.
3. Copy the result with the Copy button.

Where it stops being right

• This tool handles text. Decoding Base64 that represents a binary file (an image, say) produces bytes that are not valid text, and the tool reports that instead of showing garbage.
• Base64 output is about a third larger than the input, because every three bytes become four characters.

Questions

Is Base64 a form of encryption?

No. It is an encoding with no key: anyone can decode it instantly. Never use it to hide a password or a secret.

What is URL-safe Base64?

A variant that replaces + with - and / with _, and usually drops the = padding, so the result can sit inside a URL or a filename without being escaped.

Why did decoding fail?

Usually the input has characters outside the Base64 alphabet, was cut off partway through, or decodes to bytes that are not valid UTF-8 text.