Base64 Encoder/Decoder

Encode text or files to Base64 and decode Base64 strings back to their original content.

Developers embedding images in CSS data URIs or encoding auth tokens in API calls.

How to use it

  1. Choose encode or decode

    Pick whether you want to encode text or a file into Base64, or decode a Base64 string back to its original.

  2. Paste text or upload a file

    To encode, paste text or drop in any file. To decode, paste the Base64 (or Base64URL) string.

  3. Copy or download

    Copy the encoded string to your clipboard, or download the decoded file.

Why use this tool?

Base64 is the standard way to carry binary data — images, files, credentials — through channels that only safely handle text, and it turns up all over development. You hit it when embedding an image directly in CSS or HTML as a data URI, building an HTTP Basic Auth header, reading a JWT, storing a small asset in JSON, or moving binary payloads through APIs and email. Doing the conversion by hand is impossible, and writing a throwaway script every time is a waste. This tool encodes and decodes Base64 instantly, for both plain text and full files, with support for the URL-safe Base64URL variant used in tokens. Everything runs in your browser, so credentials, keys, or private files you paste in never touch a server — a real concern with online encoders. Encode text or upload a file to get its Base64 string, or paste a string to decode it back and download the original file. No account, no limits.

Common use cases

Web development

Turn small images and fonts into Base64 data URIs to embed them inline in HTML/CSS and avoid extra network requests.

API authentication

Build HTTP Basic Auth headers by encoding "username:password" to Base64.

JWT & token inspection

Decode the Base64URL-encoded parts of a token to read its header and payload claims.

Data transport

Encode binary blobs so they can ride safely inside JSON, XML, query strings, or email bodies.

Debugging

Quickly decode a mysterious Base64 string from a log, config, or response to see what it actually contains.

Frequently asked questions

Is my data sent to a server?

No. All encoding and decoding happen entirely in your browser, so credentials, keys, and private files never leave your device.

What is Base64URL?

A URL- and filename-safe variant that replaces + with - and / with _, and usually drops padding. It is what JWTs use.

Can I encode binary files?

Yes. Upload any file to get its Base64 string, ready for a data URI or an API payload — and decode it back to download the original.

Why does Base64 make data bigger?

It represents every 3 bytes as 4 text characters, so the output is about 33% larger than the input. That overhead is the cost of being text-safe.

Does Base64 encrypt my data?

No. Base64 is encoding, not encryption — anyone can decode it. Never use it to protect secrets.

Is there a size limit?

Text is effectively unlimited. File encoding works well up to around 10MB.

What character set is used for text?

Text is handled as UTF-8 before encoding, so accented characters and emoji round-trip correctly.

Is it free?

Yes — completely free, no sign-up, and no limits.

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