Our online Excel converter is a free way to convert different file formats to and from Excel format (XLS or XLSX) online. The Microsoft Excel spreadsheet (.XLS) is a binary format that was introduced in 1987 that comes with one or more worksheets, which display & store the data in a table format. An online XLS converter is typically considered to do instant XLS files conversion. In 2007, MS introduced the Excel Open XML spreadsheet (XLSX) format that contains arranged rows and columns and different formatting elements. If you need to perform XLSX conversions to and from other compatible file formats, then use our XLSX converter online. Remember that both Excel (.XLS) and (.XLSX) extensions are used for saving data in spreadsheets, and that’s why typically they are referred to as just Excel spreadsheets. No matter either you want to convert files to and from XLS or XLSX spreadsheet, this Excel converter does instant and quality transformation.