CaLigator is a windows software for determination of equilibrium Ca2+-binding constants from (primarily) chelator competition experiments. CaLigator can be used to do least-squares fitting of the experimental data to a variety of models. In addition it can also be used before conducting the experiments for planning purposes.
CaLigator and the experimental techniques used to generate accurate binding data is presented in "Measurement of Ca2+-Binding Constants of Proteins and Presentation of the CaLigator Software", Analytical Biochemistry (2002). You can find a pdf here:
CaLigator was developed more than 10 years ago. There are some quirks that are caused by unanticipated improvements in computer hardware! If you have problems seeing all the graphical elements in the program, you may have to reduce the screen resolution.
Below you'll find the CaLigator program in a zip file that contains a windows executable, help file and test case. Best of luck!