A multiple integrating ramp analog to digital converter is provided wherein an unknown analog input signal is coupled to an integrator for a variable time. The variable time is determined by an integral number of cycles of operation of a counter which is stepped at a predetermined rate while the unknown voltage is being integrated. During this time the output voltage of the integrator goes from an initial level to a second level. When the required time has elapsed, a reference voltage of opposite polarity to the unknown input voltage is coupled to the integrator and the counter is stepped at the predetermined rate. During this time the output voltage of the integrator starts from the second level and, when the initial voltage level appears at the output of the integrator, the counter is stopped and that count then provides a digital representation of tee unknown analog input signal.