This paper aims at estimating the switching time for linear switched systems, i.e. the time instant when a sub-model is switched on while another one is switched off. Assuming that the state of the active sub-models is known, a distribution point of view is adopted to get a real-time estimation of these switching times. Real-time means that an explicit algorithm computes on-line these time instants in a fast and efficient way. Simulations illustrate the proposed techniques which is easily implementable.