Abstract: A digital apparatus for generating an energy log for instant recall and display comprising a microcomputer including microprocessor with interrupt capability, programmable timer, keyboard and digital output. The apparatus is permanently programmed in read-only memory with a task to continuously update data and time information stored in read/write memory, a task to process each interrupt corresponding to pulsed signals indicative of energy usage and to add a unit to one memory location corresponding to that type of energy usage on a given date and a task to select and display time and date and to select and display functions of the contents of the memory locations corresponding to energy usage. The tasks are entirely interrupt activated.