Convert Base64 encoded strings back to Microsoft Excel spreadsheets. Decode and download XLSX files instantly.
Paste your Base64 encoded XLSX data to convert it back to a downloadable Excel spreadsheet
Enter the Base64 string representing a Microsoft Excel spreadsheet
XLSX Validation
Validates XLSX file structure and format
Sheet Detection
Automatically counts worksheet sheets
Instant Download
Download decoded Excel spreadsheets directly
Data URL Export
Export as complete data URL for use in web applications
Valid Format
Input must be valid Base64 encoded XLSX data
File Size
Large spreadsheets may take longer to process
Privacy
Your data never leaves your browser
Compatibility
Works with Microsoft Excel 2007 and later versions
Converting Base64 encoded data back to XLSX spreadsheets allows you to retrieve Microsoft Excel files that were previously encoded for transmission or storage. XLSX files are actually ZIP archives containing XML files and other resources that make up the spreadsheet.
The tool validates the XLSX format by checking for both the ZIP signature and XLSX-specific XML structure. This ensures you're working with valid Excel spreadsheets before downloading them. It also attempts to count the number of worksheets in the spreadsheet.
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Save the reconstructed Excel file
XLSX is the file format used by Microsoft Excel since 2007. It's actually a ZIP archive containing XML files that define the spreadsheet structure, data, formatting, and charts.
The tool automatically validates the decoded data by checking for both the ZIP signature and XLSX-specific XML structure. If the data is not a valid XLSX, you'll see an error message.
Yes! The downloaded file is a standard XLSX spreadsheet that can be opened and edited with Microsoft Excel, LibreOffice Calc, Google Sheets, or any other compatible spreadsheet software.
The limit depends on your browser's memory capacity. Very large spreadsheets may take longer to process or may cause browser performance issues.
Yes! This Base64 to XLSX converter is completely free with no registration required. All processing happens locally in your browser for maximum privacy.