An A.C. electric power usage measuring and display system using microcomputer based digital processing. Power usage pulses optically sensed from a watthour meter rotary disc and time pulses sensed from the 60 Hz A.C. power line are input to a microprocessor that is programmed to calculate and display the day of the week 1 to 7, the time of day on a 24-hour clock basis, the total watthours and kilowatthours since the start of a billing period on a decimal basis, the peak interval watthours and kilowatthours on a decimal basis, the peak interval start time and end time on a 24-hour clock basis for a peak interval of predetermined time, the peak power demand in kilowatts on a decimal basis, the day of the peak demand on a weekly 1 to 7 basis, the time of the peak demand on a 24-hour clock basis, and the present demand in kilowatts on a decimal basis. This data is displayed in sequence along with a reference decimal number 1 to 12 on an electronic display built into the meter and visible through the glass cover thereof.