A method for obtaining viscosity–temperature data for glasses is provided on the basis of the characteristic points obtained by hot stage microscopy (HSM) in the range 6η)η in dPa s). In this viscosity range, sintering of glass powder compacts is observed. The method exploits the dependence of the first and maximum shrinkage temperatures (T FS and T MS) on the heating rate and on the physical parameters of the glass (surface tension and particle size distribution) during nonisothermal sintering of a compact of glass particles. The sintering kinetics can be described by the Frenkel model at the first shrinkage temperature and by the Mackenzie–Shuttleworth model at the maximum shrinkage temperature. Each model allows a viscosity value to be assigned at each temperature. By varying the glass particle size distribution and heating rates, a corresponding set of values T, η(T) was obtained for a borosilicate glass prepared in the lab and for three industrial glasses of certified composition: E-glass, a Pyrex glass and a soda–lime–silica float glass. These values are compared with viscosity data obtained with a high temperature viscometer. Different sources of error such as wide particle size distribution, irregular particle shapes and the occurrence of crystallisation concurrent with sintering are discussed.