The following packages calculate the state of the carbonate system in seawater (including pH):
* [http://cdiac.ornl.gov/oceans/co2rprt.html CO2SYS] , available as a stand-alone executable, Excel spreadsheet, or MATLAB script.
* [http://cran.at.r-project.org/web/packages/seacarb/index.html seacarb], a R package for Windows, Mac OS X and Linux (also available [https://web.archive.org/web/20060212225505/http://www.obs-vlfr.fr/%7Egattuso/seacarb.php here])
* [http://www.soest.hawaii.edu/oceanography/faculty/zeebe_files/CO2_System_in_Seawater/csys.html CSYS], a Matlab script