The .xls filename extension is a native binary file format associated with the closed source spreadsheet application Microsoft Office Excel. First introduced in 1987 with the release of Excel 2.x, the file format acts as the container for storing spreadsheet data such as work sheets, charts, and macros. Prior to Microsoft Office Excel 2007, the xls binary format was the default standard for the Microsoft Office Excel until the later adoption of the Open Document standard .xlsx. Documents to be saved in the .xls format are saved as Excel 97, 2003 documents.
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.
FreeFileConvert uses tuned encoding for XLS to XLSX conversions, preserving clarity while trimming file size. Finished audio streams instantly across phones, tablets, desktops, and modern browsers without extra tweaks.
Upload XLS files from desktop, tablet, or cloud storage, queue multiple jobs, and let the converter finish autonomously. Return whenever convenient to download synchronized XLSX 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 XLSX audio with dependable progress tracking.
.xls was extended to the Microsoft Office XML format spreadsheetML which was later succeeded by the Office Open XML specification. The format stores data as fixed sized streams and sub streams which contain cell records with actual user input cell data, formulas, cell properties, along with meta data about the file including information such as document author, date of creation, worksheet names etc. The main streams in the xls format are Workbook stream, Globals sub stream, and the worksheet sub stream.
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 XLS format from your device, Dropbox, or Google Drive.
Select XLSX 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.