This article describes the two file formats that use the ODS file extension. It also explains how to open or convert the file format that you have.

A file with the .ODS file extension is most likely an OpenDocument spreadsheet containing typical spreadsheet data, such as text, charts, images, formulas, and numbers, all placed in a worksheet full of cells.

Outlook Express 5 mailbox files also use the ODS file extension, but this is used for e-mail messages, newsgroups, and other e-mail settings. They have nothing to do with spreadsheets.

OpenDocument spreadsheet files can be opened with the free program Calc, which is part of the OpenOffice suite. The suite also includes several other applications, such as a word processor and a presentation program.