A theoretically ideal and simple dead‐time correction system for analog ratemeters is presented. It is based on the use of a correction amplifier controlled by the durations of measured pulses and it allows pulses with varied and unknown durations. A possible application area is the concentration measurement of monodispersive (or limited size distributed) particles using single particle optical counters. Experimental measurements of aerosol particle concentrations with a single particle optical counter shows that a significant extension in the measurement range is achieved.