Use the "Local file" or "Online file" buttons to specify how to upload the document to the server. Use the "local file" if you need to convert a file from your computer, in order to specify a file on the Internet, select "Online file" and in the appeared field paste the link to the file. We do not set any limits on the size of the document file, but the larger the file, the more time it will take to convert. Just be patient and everything will turn out.
To start the conversion, click the "Convert" button to start the transformation. If the conversion is successful, the file will be available in the "Conversion Results" section. If you just need to download a file, click on the file name. If you want to get other ways to save, then click on the icon to generate a QR code to upload the result to your mobile phone or tablet, and also if you want to save the file in one of the online storage services such as Google Drive or Dropbox.
Please be patient in the conversion process.
Compare XLS with XLSX
Microsoft Excel up until 2007 version used a proprietary binary file format called Excel Binary File Format (.XLS) as its primary format. Excel 2007 uses Office Open XML as its primary file format, an XML-based format that followed after a previous XML-based format called "XML Spreadsheet".
The Office Open XML file formats are a set of file formats that can be used to represent electronic office documents. There are formats for word processing documents, spreadsheets and presentations as well as specific formats for material such as mathematical formulae, graphics, bibliographies etc.
OpenOffice.org has created documentation of the Excel format. Since then Microsoft made the Excel binary format specification available to freely download.
Office Open XML documents are stored in Open Packaging Convention (OPC) packages, which are ZIP files containing XML and other data files, along with a specification of the relationships between them. Depending on the type of the document, the packages have different internal directory structures and names.