A Standard Base Period includes wages from a 12-month period of time consisting of the first four of the last five completed calendar quarters. If your claim begins in: January-February-March: Your Standard Base Period is the prior 12 months, ending the last day of September. April-May-June: Your Standard Base Period is the prior 12 months, ending the last day of December. July-August-September: Your Standard Base Period is the prior 12 months, ending the last day of March. October-November-December: Your Standard Base Period is the prior 12 months, ending the last day of June.