GMT is normally 8 hours ahead of the Pacific Standard time zone on the West Coast of the United States. However, during the period when Daylight Saving Time is observed in the United States, Pacific Standard Time changes to Pacific Daylight Time by going forward one hour. The difference between GMT and PDT is 7 hours.
To convert a time from PDT to GMT, add 7 hours to the time in PDT. For example: 4 a.m. + 7 hours = 11 a.m.
To be precise, label the time with the correct time zone. Ensure the date is correct also, because GMT can be a day ahead, depending on the time. For example, 8 p.m in PDT is the same time as 3 a.m. the next day in GMT.