Abstract: A pocket sized, electric powered bar code printer has a slot for receiving an envelope or label, interchangeably. The slot and an end stop thereof are situated so as to enable the user to easily locate the label or the lower left corner of the envelope relative to a mechanical and/or thermographic printer which is used to impart thereto the bar code used by the U.S. Post Office. A numeric keypad allows the desired postal zip code to be input to the device, and these numbers are displayed on an LCD screen, as they are entered, for review by the user prior to printing. A "clear entry" key allows the user to make needed corrections, after which depression of a "print" key initiates printing of a bar code which corresponds to the entered numbers. As long as the power is not interrupted and there is no change to the display, subsequent pieces of mail may be printed with the same code by just depressing the print key once the items are properly located in the slot.