Base64 Encode / Decode Online

How to encode and decode Base64

Paste your text and choose a direction. Encoding turns readable text into Base64; decoding turns Base64 back into text. Both run instantly in your browser.

What Base64 actually is

Base64 represents binary data using 64 printable characters: A-Z, a-z, 0 to 9, plus and slash. It exists because a lot of older infrastructure was built for text and mangles raw binary. Email is the classic case: the protocol was designed for 7-bit ASCII, so an attached image has to be re-expressed as text to survive the journey. Base64 is that re-expression.

You will also meet it in data URIs that embed a small image directly inside CSS or HTML, in JSON Web Tokens, in HTTP Basic authentication headers, and in configuration files that need to carry a certificate or key as a single line of text.

The thing people get wrong

Base64 is not encryption. It provides no security whatsoever. There is no key, no secret, and decoding it takes one step that anybody can perform, including in this very tool. Never use it to hide a password, a token or anything else sensitive; it is an encoding for safe transport, not a lock.

It also costs space. Base64 output is about 33% larger than the input, because three bytes of data become four characters of text. That is the price of making binary safe to send through text-only channels.

Frequently asked questions

Why does the output end in one or two equals signs?

Padding. Base64 works in three-byte groups, and = marks a final group that was not full.

My decode failed. What went wrong?

Usually a truncated string or stray characters picked up when copying. Line breaks and spaces in the middle are the common culprits.

Can I encode an image here?

This tool handles text. For binary files you need a file-based encoder.

Is my data sent anywhere?

No, which matters given how often Base64 strings contain tokens and credentials.