Tiny Toolkit

Base64 File Encoder / Decoder

Encode any file to a Base64 string, or paste a Base64 string to decode it back to a downloadable file. Base64-encoded files are commonly embedded in HTML data URIs, sent through APIs that don't support binary payloads, and stored in databases alongside text. The encoded string is shown in a scrollable area you can copy in one click.

All processing happens in your browser. No data is sent to any server.

Frequently Asked Questions

What types of files can I encode?
Any file type is accepted. The tool reads the raw bytes of the file and encodes them as a Base64 string, regardless of whether the file is an image, PDF, archive, or text document.
What can I do with the Base64 output?
Base64-encoded files can be embedded directly in HTML (as data URIs), JSON payloads, or CSS. They are also used in email attachments, API requests, and configuration files that do not support binary data.
How does the decode tab work?
Paste a valid Base64 string into the input, enter a filename (including the extension), and click Download File. The tool decodes the string back to binary data in your browser and triggers a file download.
Why is the Base64 output larger than the original file?
Base64 encoding expands binary data by approximately 33%, because every 3 bytes of binary data become 4 printable ASCII characters. This overhead is the cost of representing binary data as plain text.

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Related Articles

What Is Base64 Encoding? How It Works and When to Use It

Base64 converts binary data into printable ASCII text. Here's how the encoding works, why it's used in emails, APIs, and data URLs, and how to decode it.

4 min read