OpenOffice.org Calc is the spreadsheet component of the OpenOffice.org software package.
Calc is similar to Microsoft Excel, with a roughly equivalent range of features. Calc is capable of opening and saving spreadsheets in Microsoft Excel file format. It provides a number of features not present in Excel, including a system which automatically defines series for graphing based on the layout of the user's data. Calc is also capable of writing spreadsheets directly as PDF files.
The default file format for OpenOffice.org 2.0 Calc can be set to either Microsoft Excel's native file format or the OASIS Open Document Format (ODF). Calc also supports a wide range of other file formats, for both opening and saving files.
As with the entire OpenOffice.org suite, Calc can be used across a variety of platforms, including Mac OS X, Microsoft Windows, Linux, FreeBSD and Solaris. Available under the GNU Lesser General Public License, Calc is free software.