OpenOffice Calc online for XLS spreadsheets is a free extension available on the Chrome platform. Developed by officeonlinesystems, this program allows users to create, edit, and view Microsoft Excel spreadsheets in both xls and xlsx formats. With its integration with a file manager, users can easily save, upload, and download xls files.

The main features of OpenOffice Calc online include a range of wizards that guide users through advanced spreadsheet functions, flexible cell formatting options, the ability to cross-tabulate and summarize data, and the option to create formulas using words. Additionally, the Intelligent Sum Button automatically inserts a sum function or subtotal depending on the context. The program also offers a variety of templates from the Extensions repository for ready-made spreadsheet solutions.

Users can save their spreadsheets in the OpenDocument format, which is the new international standard for office documents. However, they are also free to use their old Microsoft Excel spreadsheets or save their work in Excel format or as a Portable Document Format (.pdf) file.