GMT to EST Converter

Which GMT and which EST?

Zone abbreviations are ambiguous, so this page starts by pinning both down. GMT here is Greenwich Mean Time: the IANA zone Europe/London, anchored on London. Note that GMT is also UTC±0 kept year-round, which London does not do; this page means only the London sense. EST here is Eastern Standard Time (North America): America/New_York, anchored on New York. Note that EST is also Australian Eastern Standard Time (usually written AEST); this page means only the New York sense.

GMT in the everyday sense means London time, whichever of GMT or BST (British Summer Time) is in force. London is not on GMT all year: its offset is UTC±0 while standard time applies (its January offset) and UTC+1 while daylight saving is active (its July offset). As of September 2026 it is on BST (UTC+1). Wherever this page writes GMT, read it as "London time on the date in question".

EST in the everyday sense means New York time, whichever of EST or EDT (Eastern Daylight Time) is in force. New York is not on EST all year: its offset is UTC−5 while standard time applies (its January offset) and UTC−4 while daylight saving is active (its July offset). As of September 2026 it is on EDT (UTC−4). Wherever this page writes EST, read it as "New York time on the date in question".

The difference as of September 2026

As of September 2026, New York is 5 hours behind London. London is on UTC+1 (BST, daylight saving in effect) and New York is on UTC−4 (EDT, daylight saving in effect). Subtract one offset from the other and you have the gap. As wall clocks: 9:00 AM in London is 4:00 AM in New York, 5:00 PM in London is 12:00 PM in New York, and 9:00 AM in New York is 2:00 PM in London.

Next scheduled clock changes: clocks in London go back 1 hour on Sunday, October 25, 2026 (local date), moving the offset from UTC+1 to UTC±0; clocks in New York go back 1 hour on Sunday, November 1, 2026 (local date), moving the offset from UTC−4 to UTC−5. Every one of those changes moves the gap, because the other side does not change with it.

How the gap changes through the year

Both sides of this pair observe daylight saving — London moves between UTC±0 and UTC+1, New York between UTC−5 and UTC−4 — but they do not switch on the same dates. London changes its clocks on its own calendar and New York on its own, and in the weeks between one side's switch and the other's, exactly one of them has moved. During those weeks the gap holds a value it holds only in those windows.

Over the year scanned from Sep 7, 2026, the gap takes two distinct values and changes four times. The full schedule, with dates on London's calendar and each run's length in days:

* Cut short by the edge of the scanned year: this run began before the scan started or continues past its end.

The usual state — 344 of the 365 days scanned — has New York 5 hours behind London. That is the value that holds for the largest part of the year. The briefest of the mismatch windows in the table is Oct 25, 2026 – Nov 1, 2026: 7 days at 4 hours behind, with GMT / EDT in force. Counted by who is on summer time, the scanned year splits into 211 days with both sides on summer time (5 hours behind), 21 days with only New York on summer time (4 hours behind), and 133 days with neither side on summer time (5 hours behind). Every value other than the usual 5 hours behind falls inside those 21 days with only New York on summer time.

The trap is the recurring meeting. Pin a weekly call at 9:00 AM on London's clock and, on New York's calendar, it sits at 4:00 AM for most of the year but at 5:00 AM while the gap is 4 hours behind (GMT / EDT). Pinned on New York's clock instead, the same call moves on London's calendar: 9:00 AM there is 2:00 PM in London for most of the year and 1:00 PM at 4 hours behind. Either way the meeting moves twice around each mismatch window — once when the first side switches and once when the second does — which is why the converter above evaluates the rules for the exact date rather than applying one remembered number.

Working hours that overlap

Assume a 9:00 AM to 5:00 PM day on both sides. Because the gap changes during the year, the overlap changes with it, so it is shown for each gap the pair takes:

• New York 5 hours behind London (BST / EDT or GMT / EST; 344 of the 365 days scanned): 3 hours of shared working time: 2:00 PM to 5:00 PM in London, which is 9:00 AM to 12:00 PM in New York.
• New York 4 hours behind London (GMT / EDT; 21 of the 365 days scanned): 4 hours of shared working time: 1:00 PM to 5:00 PM in London, which is 9:00 AM to 1:00 PM in New York.

The 9-to-5 window is a convention, not a fact about anyone's real hours. The Meeting Planner lets you set each side's actual working hours and shows the overlap for the exact date you are planning.

Converting EST to GMT

This page serves both directions, because the reverse conversion is the same gap with the sign flipped. As of September 2026, London is 5 hours ahead of New York, so:

• 9:00 AM GMT (London) = 4:00 AM EST (New York)
• 9:00 AM EST (New York) = 2:00 PM GMT (London)
• 5:00 PM EST (New York) = 10:00 PM GMT (London)

To run EST to GMT in the converter above, swap the From and To menus; the result shows both offsets for the date you enter and flags a day change whenever the reading lands on the previous or next calendar day. The readings above hold only while the gap is 5 hours behind; on the dates listed in the section above they move, in both directions at once.

More on these zones

• Current time in London — live clock, offset and next clock change.
• Current time in New York — live clock, offset and next clock change.
• Time Zone Converter — any city to any city, DST-correct for the date.
• Meeting Planner — overlap for your real working hours.
• All zone-to-zone converters — the other corridors on this site.

GMT to EST — frequently asked questions

Conversions are computed locally in your browser from its IANA time zone data; nothing you enter is transmitted. The schedule and offsets on this page were derived from the same database at build time, as of September 2026. Jurisdictions occasionally change DST law with short notice, and the IANA database follows reality — for legally critical timing, confirm against an official source. See the methodology page.