Drop your file here or click to upload.
Supports all standard formatsNo file selected
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What Is XLS to XLSX?
Rather than searching for desktop software just to convert xls to xlsx, you can use XLS to XLSX directly in your browser. It is free, works on mobile and desktop, and returns your result in seconds without watermarks or forced sign-ups. It is part of our file converter tools suite, built around the same idea: get things done quickly, without friction.
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Key Benefits
Technical Specifications
| Format | Max File Size | Output Quality | Browser Support | Best Use Case |
|---|---|---|---|---|
| All Standard | Up to 500MB | High (Lossless) | Chrome, Firefox, Safari, Edge | Quick conversions |
| JPG / PNG / WEBP | Up to 200MB | Adjustable (80-100%) | All modern browsers | Web optimization |
| RAW / TIFF / BMP | Up to 100MB | High (Lossless) | Chrome, Firefox, Safari | Professional editing |
How to Use XLS to XLSX — Step-by-Step Guide
Click the upload area or drag-and-drop your file into the tool interface.
Adjust the available options such as output format or quality (if applicable).
Process your file instantly with a single click.
Review the output preview to ensure it meets your expectations.
Click "Download Result" to save the converted file to your device.
Use "Clear All" to start a new conversion with a different file.
XLS to XLSX vs Desktop Software
| Feature | This Tool | Photoshop | GIMP | Squoosh |
|---|---|---|---|---|
| Cost | ✅ Free | 💲 Paid | ✅ Free | ✅ Free |
| Speed | ✅ Instant | 🟡 Moderate | 🟡 Moderate | ✅ Fast |
| Privacy | ✅ 100% Local | 🟡 Cloud sync | ✅ Local | ✅ Local |
| Ease of Use | ✅ Very Easy | 🟡 Complex | 🟡 Moderate | ✅ Easy |
Frequently Asked Questions
What is XLS to XLSX and how does it work?
XLS to XLSX is a free online tool that helps you no installs, no fees: xls to xlsx is a quick, free way to convert xls to xlsx from any device.. It processes data locally in your browser, ensuring privacy and speed.
Is XLS to XLSX completely free?
Yes, XLS to XLSX is 100% free with no hidden costs, no sign-ups, and no usage limits.
What formats does XLS to XLSX support?
XLS to XLSX supports all standard formats for its category. For detailed specifications, check the tool interface above.
Is XLS to XLSX safe to use online?
Absolutely. XLS to XLSX processes all data directly in your browser. Your files are never uploaded to any server.
Can I use XLS to XLSX on my phone?
Yes. XLS to XLSX is fully responsive and works on all devices.
How does XLS to XLSX compare to desktop software?
XLS to XLSX offers comparable quality with zero installation and instant updates.
What is the maximum file size for XLS to XLSX?
The maximum file size depends on your device's memory, but typically you can process files up to 500MB or more.
Do I need to create an account to use XLS to XLSX?
No, XLS to XLSX requires absolutely no account creation or personal information. Just open the page and start using it.
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Use Tool →Start Using XLS to XLSX Free Today
XLS to XLSX is a reliable, fast, and secure online tool designed to help you no installs, no fees: xls to xlsx is a quick, free way to convert xls to xlsx from any device.. With zero installation, no sign-ups, and 100% client-side processing, it's the perfect choice for professionals and casual users alike. Bookmark this page for quick access whenever you need it.