Convert Microsoft Excel spreadsheets to Base64 format instantly. Perfect for embedding spreadsheets in web pages, emails, and applications.
Upload an XLSX file to encode it as Base64
Supports XLSX files (Max 20MB)
XLSX Validation
Validates XLSX file structure and format
Sheet Detection
Automatically counts worksheet sheets
Progress Tracking
Real-time progress indicator for large files
Data URL Export
Export as complete data URL for direct use
File Size Limit
Maximum file size: 20MB for optimal performance
Browser Memory
Large spreadsheets may consume significant memory
Privacy
All processing happens locally in your browser
Size Impact
Base64 encoding increases file size by ~33%
Converting XLSX files to Base64 encodes the binary spreadsheet data as ASCII text characters. This allows Microsoft Excel files to be embedded directly in HTML, CSS, JavaScript, JSON, XML, or other text-based formats without requiring separate file requests.
The conversion process reads the XLSX file as binary data, then encodes it using Base64, which represents the binary data using only 64 ASCII characters (A-Z, a-z, 0-9, +, /). This increases the file size by approximately 33% but makes the spreadsheet universally compatible with text-based systems.
Embed spreadsheets directly in web applications
Send Excel files through JSON APIs and web services
Include spreadsheets as Base64 in HTML emails
Store Excel files as Base64 text in databases
< 1MB
Best for embedding
1-5MB
Use with caution
> 5MB
Avoid embedding
We support standard XLSX files created by Microsoft Excel 2007 and later, as well as compatible spreadsheets from LibreOffice Calc, Google Sheets, and other spreadsheet applications.
Base64 encoding increases file size by approximately 33% due to the conversion from 8-bit bytes to 6-bit characters. For example, a 2MB XLSX becomes about 2.7MB when encoded.
The tool can convert any XLSX file, but password protection must be handled by the spreadsheet itself. The Base64 encoding doesn't add any security features.
For small XLSX spreadsheets (< 1MB), Base64 reduces HTTP requests. For larger spreadsheets, separate files are usually more efficient due to caching and streaming capabilities.
Absolutely! This XLSX to Base64 converter is completely free with no limitations, registration, or hidden costs. All processing happens locally in your browser.