Convert Files to Base64 Online - Encode and Decode Base64 Files

What is the Base64 File Converter?

The Base64 File Converter is a versatile tool that allows you to convert any file into a Base64 encoded string and decode Base64 strings back into downloadable files. Base64 encoding represents binary data in ASCII text format, making it easy to transmit files over text-based protocols like email, JSON, or XML.

This tool works entirely in your browser, meaning your files are never uploaded to any server. You can encode images, documents, audio files, and more into Base64 format for use in data URIs, API requests, or embedding into HTML and CSS. On the flip side, you can paste a Base64 string and download the original file back to your device.

If you need to work with text-based Base64 encoding, try the Base64 Encoder/Decoder tool. For converting Base64 data URIs into actual image files, use the Base64 to Image Converter. To convert images to Base64, check out the Image to Base64 Converter.

How to Use the Base64 File Converter

This tool provides two main functions:

File to Base64

Click the Select File button to upload a file from your device.
The tool automatically reads the file and generates its Base64 encoded string.
Use the Copy button to copy the Base64 string to your clipboard.
Use the Download button to save the Base64 encoded representation as a text file.

Base64 to File

Paste your Base64 encoded string into the input area on the right side.
Specify the desired download Filename and file Extension.
If the Base64 string represents an image, a preview is shown automatically.
Click the Download File button to save the decoded file to your device.

Supported File Types

The Base64 File Converter supports all file types including images (PNG, JPEG, GIF, WebP, SVG, BMP), documents (PDF), compressed files (ZIP), text files (TXT, HTML, CSS, JavaScript, JSON), audio files (MP3, WAV, OGG), and video files (MP4, WebM). Since the conversion happens entirely in your browser, there is no file size limit beyond what your browser can handle.

Common Use Cases for Base64 File Encoding

Embedding images in HTML/CSS: Use data URIs to embed small images directly in your code.
API data transfer: Send file contents as Base64 strings in JSON payloads.
Email attachments: Encode files in Base64 for MIME email attachments.
Database storage: Store small files as text in database fields.
WebSocket communication: Transmit file data over text-based WebSocket protocols.

For encoding text strings to Base64, use our Base64 Encoder/Decoder. For URL-safe Base64 encoding, check out the URL Encoder/Decoder.

Privacy and Security

All file processing happens locally in your browser using the FileReader API. No files are uploaded to any server. Your data remains completely private and secure on your device. For sensitive files, you can confidently use this tool without privacy concerns.

Frequently Asked Questions

What is Base64 encoding?

Base64 encoding is a method of converting binary data into ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). It is commonly used to transmit binary data over text-based protocols. Each Base64 character represents 6 bits of the original binary data, resulting in about 33% size increase compared to the original.

Is there a file size limit for the Base64 File Converter?

There is no hard limit imposed by the tool itself. However, very large files (hundreds of megabytes) may cause performance issues in your browser due to memory constraints. For most common use cases like encoding images, documents, or small audio files, the tool works instantly.

Can I use this tool offline?

Yes, the Base64 File Converter processes all data client-side in your browser. Once the page is loaded, you can use it without an internet connection. The file reading and Base64 conversion happen entirely on your device.

How do I convert a Base64 string back into a file?

Paste your Base64 string into the right-side input area. The tool automatically detects the file type if the string includes a MIME type prefix (like "data:image/png;base64,"). Set the filename and extension, and click "Download File" to save the decoded file to your device.

What is the difference between Base64 encoding for text and for files?

Text-based Base64 encoding converts text strings to Base64 representation, while file-based encoding reads the raw binary data of a file and encodes it. File encoding produces a data URI format that includes the MIME type, making it compatible with HTML/CSS embedding and other web standards. For text encoding, use the Base64 Encoder/Decoder.

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