Base64 is a way to write any data with only 64 safe characters: letters, digits, + and /. It is used to put binary data or special characters where only plain text is allowed, such as in email attachments, data URLs, HTTP headers and JSON.

Is Base64 encryption?

No. Base64 is an encoding, not encryption. Anyone can decode it, so never use it to protect passwords or other secrets.

What is URL-safe Base64?

A variant that replaces + with - and / with _, and usually leaves out the = padding at the end, so the result can go in a URL or a file name without being changed. JSON Web Tokens use it.

Why does decoding say the Base64 holds binary data?

The Base64 you pasted holds something other than text, such as an image, a PDF or compressed data. This tool decodes text only.

Why is the encoded text longer than the original?

Base64 uses 4 characters for every 3 bytes, so encoded data is about a third larger. Letters with accents and emoji take more than one byte in UTF-8, so they grow a little more.

Is my text sent to a server?

No. Everything runs in your browser, so you can encode and decode tokens and private text without it leaving your device.

Base64 encoder and decoder

Encode text to Base64 or decode it back, as you type.

URL-safe

Encode

Decode

Input

Result

Base64 to text and back

Paste text to encode it to Base64, or paste Base64 to decode it. The conversion handles every language and emoji through UTF-8, accepts standard and URL-safe Base64, and happens entirely in your browser.

Encode and decode in one place

Switch between Encode and Decode, or use Swap to send the result back to the input and convert it the other way.

Accents and emoji work

Text is converted to UTF-8 before encoding, so letters like é and ç, other alphabets and emoji survive the round trip. The btoa function in a browser console cannot do that.

URL-safe Base64

Turn on URL-safe to use - and _ instead of + and / and drop the = padding, the variant used in JSON Web Tokens, URLs and file names. Decoding accepts both variants.

Clear errors

Line breaks and spaces in pasted Base64 are ignored. If the text is not valid Base64, or it holds a file rather than text, you are told so instead of getting garbled output.

Runs in your browser

Encoding and decoding happen on your device. Nothing you paste is sent to Fast Note.

Instant and free

Results appear as you type, and Copy puts them on your clipboard in one click. No account, nothing to install.

Decoding the middle part of a JSON Web Token? Paste the result into the JSON formatter to read it.

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