XLS→XLSXConverter
Convert your XLS files to XLSX format instantly. Free, fast, and secure - your files never leave your browser.
↔ Convert XLSX to XLS insteadDrop file or click to browse
Max 100MB • Auto-deletes after 3 min
How to Convert XLS to XLSX
Upload Your File
Drag & drop your XLS file or click to browse. Files up to 100MB are supported.
Convert
Click "Convert to XLSX" and wait a few seconds for processing.
Download
Download your converted XLSX file instantly. No registration needed.
Why Convert XLS to XLSX?
Converting XLS to XLSX improves compatibility, reduces file size, or enables your content to work with specific applications and platforms that require the XLSX format.
About XLS and XLSX
What is XLS?
XLS is the legacy Microsoft Excel binary format used before 2007. While superseded by XLSX, it remains necessary for compatibility with older Excel versions and some enterprise systems.
What is XLSX?
XLSX is Microsoft Excel's default spreadsheet format based on Open XML. It's the global standard for data analysis, financial modeling, budgets, and business reporting.
Frequently Asked Questions
How do I convert XLS to XLSX?
Upload your XLS file using the converter above, then click "Convert". Your file will be processed and you can download the converted XLSX file immediately. The entire process takes just seconds.
Is it free to convert XLS to XLSX?
Yes, ModConvert is completely free to use. There are no hidden charges, no registration required, and no watermarks on your converted files.
Is my XLS file safe when converting?
Absolutely. Your files are processed securely and are never stored permanently on our servers. Files are automatically cleaned up after conversion to protect your privacy.
What is the maximum file size for XLS to XLSX conversion?
You can convert XLS files up to 100MB in size. This covers most common use cases for spreadsheet files.
Can I convert multiple XLS files at once?
Yes, you can upload and convert multiple XLS files. Each file will be converted to XLSX format individually for the best quality results.