Eastern Standard Time (EST) = GMT-5
Eastern Daylight Time (EDT) = GMT-4
http://wwp.eastern-standard-time.com/

Pacific Standard Time PST = GMT-8 PDT = GMT-7 (USA & Canada)
http://wwp.greenwichmeantime.com/time-zone/usa/pacific-time/

PDT - Pacific Daylight Time
http://www.timeanddate.com/library/abbreviations/timezones/na/pdt.html

PST - Pacific Standard Time
http://www.timeanddate.com/library/abbreviations/timezones/na/pst.html