BTT is UTC+6 Hours. Bhutan Time is 6 hour ahead of Coordinated Universal Time (UTC). BTT timezone is observed in Asia. Therefore, to find the current time in this time zone one has to add 6 hour to the present time in Coordinate Universal Time.
BTT is 13 hour ahead to Pacific Daylight Time-PDT the local time zone and hence to convert the PDT to CET add 13 hours from Pacific Daylight Time.