ConCalc

This tool can be used for processes where one has to prepare multiple liquid samples of a fixed volume but of different concentrations. Usually one has two stock solutions of different concentrations and a solvent.

As an example:
We have two stock solutions of salt A and protein B, both mixed in the same solvent, here it's water. We intend to obtain a sample of a specific volume of 1 milliliter and it needs to be of a fixed concentration of A and B. This tool can provide with the volumes needed from stock solutions of A and B as well as water to end up with the end volume of 1 ml.