Flash point (FP) is an important parameter for assessing the safety of chemical compounds. Many empirical approaches have been developed to predict FPs based on molecular structure, sometimes involving a large number of descriptors and resulting in class-specific equations. We demonstrate in this work that a satisfying and rather general prediction of the saturation pressure at the FP can be achieved using only the molecular surface area. This relation in combination with any experimental or computational method for calculating temperature-dependent vapor pressures thus allows for the prediction of the FP. In a second step, we calculate the FPs of mixtures using COSMO-RS activity coefficients. By using the proposed method, we were able to calculate flash points without the need for data typically generated in experiments such as normal boiling points or enthalpies of combustion, although experimental pure-compound FPs and vapor-pressure data still can be used to increase the prediction quality.