The .xlsx is an open source filename extension format developed by Microsoft in collaboration with ISO/IEC and ECMA. It is part of the Open Document family of file formats. The .xlsx is associated with spreadsheet authoring applications particularly with Microsoft's Office Excel 2007 and above. The format has existed since 2005 and is also supported by several other proprietary and open source spreadsheet authoring software other than Microsoft's Office Excel. The xlsx format is the default filename extension for all spreadsheet documents produced using Microsoft Office Excel 2007 SP2 and above.
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FreeFileConvert uses tuned encoding for XLSX to SXC conversions, preserving clarity while trimming file size. Finished audio streams instantly across phones, tablets, desktops, and modern browsers without extra tweaks.
Upload XLSX files from desktop, tablet, or cloud storage, queue multiple jobs, and let the converter finish autonomously. Return whenever convenient to download synchronized SXC results on any device you rely on.
Process up to 5 files sized 1000 MB per batch without splitting queues manually. Mixed-format uploads convert together, producing consistent SXC audio with dependable progress tracking.
The xlsx filename extension is a compressed archive with an xml directory structure. It is specified in the open standard ISO/IEC 29500-1:2012. .xlsx files do not support macros by design, for that, the .xlsm format should be used. A free compatibility update allows older versions of Microsoft Office Excel such as Office 2003 to open .xlsx documents.
Upload your document file in the XLSX format from your device, Dropbox, or Google Drive.
Select SXC as the output format and click Convert. Adjust optional settings if needed.
Download the converted document file. Each file stays available for up to 5 downloads.