GMT to EST

GMT is ahead of EST by 4 hours today

On 19 August 2026, Greenwich Mean Time is on GMT at UTC+00:00 and Eastern Standard Time is on EDT at UTC-04:00. The gap between them is 4 hours, with EST behind. So 9:00 am in GMT is 5:00 am in EST, and 5:00 pm in GMT is 1:00 pm in EST. Going the other way, see EST to GMT.

The gap is not constant, and that is the part that catches people out

Eastern Standard Time is currently observing daylight saving and changes next on 1 November 2026. Greenwich Mean Time does not observe daylight saving, so the gap moves only when Eastern Standard Time changes its clocks — twice a year, by one hour.

When you can actually both be at work

Taking a working day as 9:00 am to 5:00 pm local at each end, there are 4 overlapping hours in a normal day. In GMT that window runs from 1:00 pm to 5:00 pm, which is 9:00 am to 1:00 pm in EST. Anything outside it needs one side to start early or finish late.

Zone rules are set by legislation and change, sometimes at short notice. This page is built against tzdata 2026a, last reviewed 2026-08-18. Quarterly. Zone rules change by legislation, sometimes at short notice. Version and review date are shown on every zone page. The converter above reads your browser's own copy of the zone database, so if a rule has changed since this page was built the live answer follows the new rule.

Every convention used above — whether the start date counts, how month ends are clamped, which holidays close an office — is written out on the methodology page, including the daylight-saving rules behind the 4-hour gap above.