This study addressed the problem of measuring the total mass of molten salt in a nuclear system such as a nuclear fuel electrorefiner or a molten salt reactor. In theory, soluble tracers can be added to an unknown amount of salt. Measurement of the tracer concentration after allowing time to homogenize the salt and elemental analysis can be used to calculate the total mass of salt in the system. In this study, the mass of a molten salt mixture of equimolar NaCl-CaCl2 was measured using this method for several sequential additions of the tracer salt. Two different tracers (CeCl3 and KCl) with known mass were used in determining the total mass of NaCl-CaCl2 salt in a crucible at 650°C. By limiting the method to tracer concentrations higher than 1.1 wt%, the average mass determination error was 2.39% and 1.82% for CeCl3 and KCl, respectively. Mass estimations were mostly high by this amount compared to the actually known mass.