Base64 Encoder and Decoder

What is base64 encoder and decoder?

Base64 is used to carry binary data inside text based systems, such as emails, JSON and data URLs. It makes data about one third larger.

This tool supports Unicode text, so accented letters and emoji encode and decode correctly.

How to use the base64 encoder and decoder

1. Pick encode or decode.
2. Paste your input.
3. Press Calculate and copy the output.

How the base64 encoder and decoder works

Text is converted to UTF 8 bytes and the bytes are mapped to the 64 character Base64 alphabet in groups of three, with equals signs added as padding.

Worked example

Common uses of the base64 encoder and decoder

• Embedding a small image or font directly in CSS or HTML.
• Reading the payload of a token or an email header while debugging.
• Sending binary data inside JSON or XML.
• Decoding a Base64 string copied from a log.
• Learning how binary to text encoding works.

Tips and common mistakes

Base64 is not encryption. Anyone can decode it, so never use it to hide secrets.

URL safe Base64 swaps plus and slash for minus and underscore. Replace them before decoding if needed.

Background: what to know before you rely on it

Many older protocols, such as email, were designed for plain text. Base64 solves the problem of sending binary files through them by using only 64 safe characters: capital and lowercase letters, digits, plus and slash. Every three bytes become four characters, so data grows by about a third. The equals sign at the end pads the last block. A URL safe variant swaps plus and slash for minus and underscore. Base64 is an encoding and not encryption. Anyone can decode it, so passwords and secrets must never be protected by it alone.

Private, free and fast

This tool runs entirely in your browser. What you type or choose is not uploaded to a server and is not saved after you close the page, which keeps it fast and private. It is free to use as often as you like. See more in all developer tools, or browse the full list of tools.

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Results are for information and education. For legal, financial, medical or security decisions, check with a qualified professional. Do not paste live secrets into any website.