RunConvert

XLSX Converter

Convert files to and from XLSX online for free. Fast, secure, and high-quality file conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

01

Upload your file

Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

02

Choose an output format

Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

03

Convert & download

Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

What is an XLSX file?

The XLSX format is the default XML-based spreadsheet file introduced in Microsoft Office 2007, adhering to the Office Open XML (OOXML) standard (ECMA-376 and ISO/IEC 29500). It replaces the binary BIFF structure of legacy XLS files with a ZIP-compressed container holding individual XML files for workbook data, worksheet structure, and metadata. By design, XLSX files strictly exclude Visual Basic for Applications (VBA) macros to prevent malware propagation, distinguishing them from the macro-enabled XLSM format.

How to open an XLSX file

As an industry-standard open format, XLSX is supported natively by Microsoft Excel, Apple Numbers, and Corel Quattro Pro. Cross-platform open-source suites like LibreOffice and Apache OpenOffice provide full read/write capabilities. Cloud-based platforms, including Google Sheets and Microsoft Excel for the Web, allow direct editing in a browser without local software installation.

XLSX Technical Info

Full Name
Excel Open XML Spreadsheet
Developed By
Microsoft
Initial Release
2007
MIME Type
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

3,000+ conversions supported

Every popular and niche format covered - video, audio, image, document, archive and more. New formats added regularly.

Fast, cloud-powered

No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

Secure & private

Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

Free - no account needed

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.