Convert Greenwich Mean Time to Eastern Daylight Time (GMT to EDT)

Understanding GMT and EDT Time Zones

Greenwich Mean Time (GMT)

Greenwich Mean Time is observed in undefined and uses the offset UTC+0. Major cities in this time zone include London, Dublin, Lisbon. This time zone covers parts of Europe and/or Africa, home to major financial and cultural centers.

Eastern Daylight Time (EDT)

Eastern Daylight Time operates at UTC-4, covering undefined. Key cities include New York, Washington DC, Miami, Atlanta, Boston. The 4-hour backward offset from GMT means that when professionals in London start their workday at 9:00 AM, it is already 5:00 AM in New York.

GMT is also commonly referred to as London time, UK time, British time, England time. EDT is also known as Eastern Daylight, Eastern Time, ET, East Coast time, New York time. So if you are searching for London time to Eastern Daylight, this is the same conversion as GMT to EDT.

Complete GMT to EDT Conversion Table

The table below shows every two-hour increment converted from Greenwich Mean Time to Eastern Daylight Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.

Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.

Scheduling Between GMT and EDT

For business scheduling, the optimal overlap window between GMT and EDT falls roughly between 1:00 PM and 5:00 PM GMT. This ensures both London and New York teams are within standard working hours.

The moderate 4-hour gap between GMT and EDT means that there is a partial overlap of business hours. Teams can typically find a 3–4 hour window that works for both sides without requiring anyone to work outside normal hours.

Travel Between London and New York

Travelers flying from London to New York should adjust their sleep schedule 4 days before departure at a rate of one hour per day. For this time difference, gradual adjustment reduces jet lag dramatically.

Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 4-hour shift between GMT and EDT, plan for about 4 days to fully acclimate.

Daylight Saving Time Considerations

During standard time months (November through March in the US), this offset is fixed. However, if either zone observes daylight saving time, the difference may temporarily shift by one hour during transition weeks in spring and autumn.

For the GMT to EDT conversion specifically: GMT (UTC+0) and EDT (UTC-4) both observe DST. When both zones transition on different dates, the offset temporarily shifts by one hour for a few weeks. Always verify during March–April and October–November.

Related Time Zone Conversions

References & Resources

• TimeAndDate.com — World Time Zones
• NIST — Official US Time Standard
• IANA Time Zone Database
• Wikipedia — Time Zone Abbreviations
• WorldTimeServer — Current Times Worldwide
• Royal Observatory Greenwich

Frequently Asked Questions