Abstract Fluid inclusions (FI) that homogenize by halite disappearance are common in some geological environments, and interpretation of microthermometric data from these inclusions has been limited by the lack of a model describing the PVTX relationships over the complete range of PTX conditions found in nature. In this study, a system of equations has been developed that can be used to estimate salinity, pressure and density of FI that homogenize by halite disappearance. The salinity, pressure, density and dP/dT slope of the FI isochore are calculated as functions of liquid–vapor homogenization temperature (Th) and halite dissolution temperature (Tm). The equations are based on a numerical model describing the isochoric pressure–temperature trajectory followed by halite-saturated fluids during heating. The model is valid for Th and Tm from 100 to 600°C, and for pressures along the liquid–vapor–halite curve to 300MPa.