EST to GMT

EST is behind GMT by 4 hours today

On 28 August 2026, Eastern Standard Time is on EDT at UTC-04:00 and Greenwich Mean Time is on GMT at UTC+00:00. The gap between them is 4 hours, with GMT ahead. So 9:00 am in EST is 1:00 pm in GMT, and 5:00 pm in EST is 9:00 pm in GMT. Going the other way, see GMT to EST.

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, when clocks go back an hour. Greenwich Mean Time does not observe daylight saving at all, so the whole of the seasonal change comes from the EST side: the gap moves by an hour twice a year even though nothing changes in Greenwich Mean Time.

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 EST that window runs from 9:00 am to 1:00 pm, which is 1:00 pm to 5:00 pm in GMT. 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 — and so does everything above, which is worked out from the same database when you open the page.

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.