Buffer Calculator is an online tool for the design and preparation of thermodynamically corrected buffers. The tool makes corrections for the temperature at which the buffer will be used, makes Debye-Huckel corrections for the effect of ionic strength on pKa, and describes two ways (titration or by accurate weight) for preparation of the recipe. Select from 36 varying pKa buffering agents. Choose the buffer species you want to use, and enter parameters for volume, pH, and concentration of buffer species. Then, include the option to modify the ionic strength by addition of neutral salt. Finally, enter the temperature at which you'll use the buffer, and the temperature at which you'll make it up (these are often not the same). The 'Recipe’ button will then open a new window with a recipe, that you can print, or if you wish, copy the information to a lab notebook.