Encode / decode Base64

What is Base64?

Base64 is an encoding that turns any data into a string of safe characters: upper and lower case letters, digits, + and /, padded where needed with =. It is used to carry text or binary data through channels designed for plain text: emails, JSON files, web addresses, HTTP headers.

Using the tool

1. Choose the direction: Text → Base64 to encode, Base64 → Text to decode.
2. Paste your content into the input field, then click "Convert".
3. Copy the result, or click "Use the result" to send it back to the input and chain another conversion.

The tool handles UTF-8: accents, non-Latin scripts and emojis are preserved in both directions.

An example

The trailing = signs are padding: Base64 splits data into groups of 3 bytes and fills in the last group if it is incomplete.

Where do you come across Base64?

• Email attachments are sent in Base64: that is why a file weighs about a third more inside the message.
• Images embedded in a web page or stylesheet, in the form data:image/png;base64,….
• Authentication tokens (JWT) and HTTP Basic authentication.
• Keys and certificates in PEM format.

Base64 is not encryption

This is a common mistake: Base64 decodes instantly, with no key or password. It protects nothing. Never use it to "hide" a password or sensitive data; that takes real encryption.

The URL variant

The characters + and / have special meanings in web addresses. The "base64url" variant, used notably in JWTs, replaces them with - and _ and often drops the =. To decode such a string here, first replace - with + and _ with /.

Frequently asked questions

Is my data sent anywhere?

No, everything is encoded and decoded locally in your browser.

Why does decoding give an error?

The string is probably not valid Base64: an extra character, a missing piece, or the base64url variant with "-" and "_". Check that you copied the whole string.

Does Base64 protect my data?

No. It is not encryption: anyone can decode it. It only serves to carry data in a text format.

Why is the result longer than the original?

Base64 represents 3 bytes with 4 characters: the result is about a third longer than the input data.