gretl is an open-source statistical package, mainly for econometrics. The name is an acronym for Gnu Regression, Econometrics and Time-series Library.
It has a graphical user interface (GUI) and can be used together with X-12-ARIMA, TRAMO/SEATS, R, Octave, and Ox. It is written in C, uses GTK+ as widget toolkit for creating its GUI, and uses gnuplot for generating graphs. As a complement to the GUI it also has a command-line interface.
gretl can output models as LaTeX files.
Besides English, gretl is also available in Greek, Chinese, Basque, Catalan, Czech, German, French, Italian, Albanian, Polish, Portuguese, Russian, Spanish and Turkish.
gretl has been reviewed several times in the Journal of Applied Econometrics and in the Journal of Statistical Software.
Supported data formats
gretl offers its own fully documented, XML-based data format.
It can also import ASCII, Comma-Separated Values, databank, EViews, Excel, Gnumeric, GNU Octave, JMulTi, OpenDocument Spreadsheet, PcGive, RATS 4, SAS xport, SPSS, and Stata files. It can export to GNU Octave, R, Comma-Separated Values, JMulTi, and PcGive file formats.