A number of mathematical methods exist to characterize the underlying mechanism of the thinning and break-up of a liquid jet. These methods however, have not been applied to fluids used in inkjet printing. In this work, we used filament stretching experiments to demonstrate the applicability of similarity solutions found in literature to determine the dominating thinning mechanism for a variety of sample fluids. The thinning velocities and break-up times were computed and compered with the experimental results from the filament stretching. We observed that an additional correction factor was required to match the used similarity solutions with the experimental data. Furthermore, we could calculate the break-up time of the filament experiment from the bulk data of the sample fluids. The calculation was used to predict the overall break-up time of a liquid jet emerging from the nozzle of an inkjet printhead. The results were in good agreement with the general limits of drop formation. Differences between the required pre-factors and from literature were observed and need to be investigated further.