Convert EST to GMT Eastern Standard Time ↔ Greenwich Mean Time Free Online Secure
Type a time in EST and read it in GMT straight away. The offset is +5 h, the arithmetic wraps at midnight, and the answer says which day it lands on.
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Through the day — Convert EST to GMT (Eastern Standard Time ↔ Greenwich Mean Time)
| EST | GMT |
|---|---|
| 00:00 | 05:00 |
| 03:00 | 08:00 |
| 06:00 | 11:00 |
| 09:00 | 14:00 |
| 12:00 | 17:00 |
| 15:00 | 20:00 |
| 18:00 | 23:00 |
| 21:00 | 02:00 |
Where these units come from
Until the middle of the nineteenth century every town kept its own noon, set by the sun overhead, and nobody minded that the next town was four minutes behind. Railways ended that: a timetable cannot be written for a hundred local noons. Britain put its railways on Greenwich time in 1847, and in 1884 the International Meridian Conference in Washington chose Greenwich as the prime meridian and sketched the twenty-four-hour scheme we still use. Greenwich Mean Time was the world's reference until 1972, when Coordinated Universal Time replaced it: UTC is kept by atomic clocks and tied back to the turning Earth by leap seconds. The abbreviations on this page name standard time — the winter setting — which is why each one is a fixed number of hours rather than something that drifts through the year.
Where you meet them
A time zone becomes real the moment two people in different places have to agree on one moment: a call between offices, a flight that lands before it took off, a market that opens while you are asleep, a deadline written in somebody else's afternoon. Server logs, train and flight schedules and anything stamped with a time are kept in UTC precisely so that the question can always be settled, no matter whose clock was on the wall.
Questions people ask
What about summer time?
The offsets here are standard-time offsets, the ones a zone keeps in winter. Where summer time is observed, the same places move one hour further on for part of the year and take a different name: Central European Time becomes Central European Summer Time, Eastern Standard Time becomes Eastern Daylight Time. The switching dates are not the same in every country, and the two hemispheres change in opposite months, so for a date inside a summer-time period add an hour to whichever side observes it.
Why isn't every difference a whole number of hours?
Because offsets are decided by governments, not by geometry. India is half an hour off the hour, at UTC+05:30; Nepal is three quarters, at UTC+05:45; the Chatham Islands are at UTC+12:45. Any of these can be changed by law, and several countries have moved their offset within living memory.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Sending an Eastern time to a British audience
You are in New York, Boston, Atlanta or Toronto and you have an announcement to send to people in Britain, Ireland or West Africa. The time you have in mind is Eastern Standard Time, and your readers think in Greenwich Mean Time. To convert EST to GMT, add five hours. A webinar at 11:00 EST starts at 16:00 GMT. A release at 8:30 EST goes live at 13:30 GMT. Anything from 19:00 EST onward lands on the next calendar date in Greenwich, so 21:00 EST on Friday is 02:00 GMT on Saturday.
This page walks through the rule, supplies a quick lookup table, and describes the quirks that matter to an American writing for a British audience: the twelve-hour clock, the four-week period when the gap shrinks, the differences between EST and ET, and a series of practical scenarios from auctions to pre-market trading. The conversion runs in your browser, so nothing you type is sent anywhere.
The method
Add five hours to the Eastern time
London is five hours ahead of the Eastern Standard clock in winter. If you take 10:00 EST and add five, you get 15:00 GMT. If the sum reaches 24:00 or more, subtract 24 and move to the next day: 20:30 EST plus five is 25:30, so the answer is 01:30 GMT the next day.
Eight rows to memorise
00:30 EST is 05:30 GMT. 06:15 EST is 11:15 GMT. 09:00 EST is 14:00 GMT. 12:00 EST is 17:00 GMT. 15:45 EST is 20:45 GMT. 18:00 EST is 23:00 GMT. 21:30 EST is 02:30 GMT the following day. 23:45 EST is 04:45 GMT the following day.
The twelve-hour trap
American schedules use a.m. and p.m., so convert to the twenty-four-hour clock before adding. 7:30 p.m. is 19:30, which becomes 00:30 GMT. 12 a.m. is midnight, 00:00, and 12 p.m. is noon, 12:00. If you convert EST to GMT while holding the wrong one of these, the answer is wrong by twelve hours.
Eastern Standard Time, from the sender’s side
Where it applies
EST is the winter clock of the East Coast and the Great Lakes: New York, Boston, Philadelphia, Washington, Charlotte, Atlanta, Miami, Detroit, Toronto and Montreal. In summer these places use Eastern Daylight Time, one hour ahead. When your message says “EST” in July, readers who know the difference will wonder what you meant.
Why ET is safer
American organisations typically write “ET” to mean “whichever Eastern clock is in force”. For an international audience, add the date and give the GMT or UTC equivalent as well. That removes any doubt about which of the two Eastern clocks applies.
Greenwich Mean Time, from the reader’s side
One clock for Britain in winter
GMT is used in Britain and Ireland from late October to late March, and all year in Iceland, Ghana, Senegal and several neighbours. Britons reading a notice in GMT will read it exactly as written. In summer they use British Summer Time, so a notice that says GMT between late March and late October may confuse them.
A neutral label online
On the web, GMT is also a label for the zero-offset reference: server logs, headers and certificates use it as a synonym for UTC. If you publish a time in GMT, you reach both audiences at once, the British readers and the technical ones.
How five hours changes the working day
The windows that overlap
A New York office open from 09:00 to 17:00 EST is open from 14:00 to 22:00 GMT. A London office open from 09:00 to 17:00 GMT is open from 04:00 to 12:00 EST. The shared window runs from 14:00 to 17:00 GMT, which is 09:00 to 12:00 EST. If you want to reach a London colleague, call before noon.
What you can do with an afternoon
Work you finish by 12:00 EST arrives in London at 17:00 GMT, just as the office closes. Work you finish by 17:00 EST arrives at 22:00 GMT, long after the day. The practical result is that Londoners often read New York messages the next morning, so a sender who wants a same-day reply should post before lunch.
The study-abroad version
A student from Ohio studying at an English university phones home in the evening, at 19:00 GMT. That is 14:00 EST at home, an ideal time. A call at 23:00 GMT reaches the family at 18:00, just as dinner is served. A call at 05:00 GMT, however, finds the household at midnight, so it needs to be agreed in advance.
The weeks when five hours is wrong
Different start dates
The United States moves its clocks on the second Sunday of March and the first Sunday of November. Europe does it on the last Sunday of March and the last Sunday of October. In 2026 that gives 8 March and 1 November for America and 29 March and 25 October for Britain.
Four weeks of difference
From 8 March to 28 March, New York is on EDT while London is on GMT, so you add four hours instead of five. From 25 October to 31 October, London has returned to GMT while New York is still on EDT, so you add four hours again. Everywhere else, the sum is five: in winter from EST to GMT and in summer from EDT to BST.
What to do
When you convert EST to GMT for a date in those weeks, count from the Eastern clock that is actually showing. 10:00 on a New York wall in the middle of March is 14:00 GMT, not 15:00. If in doubt, add the date and both zones to the message.
An online auction that ends at 7 p.m.
The bidder in Britain
Online auctions often end at a stated Eastern time. A listing that closes at 7:00 p.m. EST closes at midnight GMT. A British bidder who wants to place a last-second bid must be awake at midnight or must set up a sniping tool. The seller who lists in Eastern time forgets that the end falls in the small hours of the next date.
The seller’s habit
If your buyers are mostly in Britain, end the auction at 2:00 p.m. EST, which is 19:00 GMT, a time when people at home are free.
Pre-market and after-hours trading
Windows outside the main session
The main American stock session runs from 9:30 a.m. to 4:00 p.m. Eastern. Pre-market trading begins at 4:00 a.m., which is 09:00 GMT, and after-hours trading runs until 8:00 p.m., which is 01:00 GMT the next day. London traders therefore see American quotes move while the London market is already open.
Why it matters to a retail investor
A British investor who sees a headline at 12:00 GMT can react before New York opens at 14:30 GMT. The “convert EST to GMT” calculation turns an abstract Eastern time into the minute at which the order could run, which helps in planning, though not in advice about what to buy.
Webinars, workshops and product launches
Choosing the hour
Many organisers pick 11:00 EST because it suits the American East and also reaches Britain at 16:00 GMT and continental Europe at 17:00 CET. West Coast attendees would join at 08:00 PST, early but tolerable. It is the closest thing to a universal webinar hour in the northern winter.
Putting it in the invitation
Write the event as “Tuesday 13 January, 11:00 EST / 16:00 GMT”. Add a link to a calendar file that holds the instant in UTC. Then people from any zone see the event at the right time, and the “convert EST to GMT” calculation on your own copy is only for checking.
Customer support across the Atlantic
When your call centre is open
A support line open from 08:00 to 20:00 EST is open from 13:00 to 01:00 GMT. For a British customer, that is from lunchtime until just past midnight. It excludes the early morning entirely, so someone who calls at 07:00 GMT will reach a recorded message.
The shift handover
Companies that run a follow-the-sun desk hand over from New York to London at 04:00 EST, which is 09:00 GMT, and hand back at 12:00 EST, 17:00 GMT. A short row of times in the staff handbook prevents most mistakes.
Live shows, podcasts and streams
The late-night host
A late-night talk show recorded at 17:30 EST and aired at 23:35 EST reaches British screens on delay, but a streaming version posted at 23:35 EST appears at 04:35 GMT. Fans in Britain who rise at 07:00 see it waiting.
Weekly shows
A podcast that goes live every Wednesday at 6:00 a.m. EST is published at 11:00 GMT. A UK listener commuting at 08:00 GMT will have to wait three hours, but the episode is ready for the lunch break.
Phones, texts and polite hours
Respecting the other clock
A call at 6:30 p.m. EST is at 23:30 GMT. It is a reasonable hour for the caller and an uncomfortable one for the recipient in Britain, who may already be in bed. A message at 8:00 a.m. EST arrives at 13:00 GMT, an excellent time. As a rule, contact British friends before 1:00 p.m. EST and Asian friends before 8:00 a.m. EST.
Rule of thumb
Anything you send after 5:00 p.m. EST lands after 22:00 GMT. Apply the “convert EST to GMT” calculation before dialing or typing, and you avoid waking people.
Fantasy leagues and sports deadlines
Lineup locks
An online sports game that locks its rosters at 1:00 p.m. EST on Sunday locks them at 18:00 GMT. British participants who plan to adjust their team during Sunday lunch have to remember that the cutoff may come before the evening kick-offs.
The trading deadline
A league deadline set at midnight EST on a Wednesday is 05:00 GMT on Thursday. For members in Britain, there are still five hours after midnight to submit a change, which makes the deadline feel like a Thursday-morning one.
Conferences and calls for papers
Academic deadlines
A call for papers that closes on “1 February, 11:59 p.m. EST” closes at 04:59 GMT on 2 February. Researchers in Britain who submit at 02:00 on 2 February are still inside the window, whatever their calendar says.
Reviewer calls
When a programme committee meets at 10:00 EST, its British member joins at 15:00 GMT and the member in Bucharest at 17:00. A well-run committee gives all three times in the agenda.
Elections and live results
Poll closing times
In many eastern American states, polls close at 7:00 p.m. local time. During the November general election, the East is on EST, so the first polls close at midnight GMT. British broadcasters stay up until the early hours, and results that matter often arrive between 02:00 and 06:00 GMT.
How to plan
If you are a viewer in the United Kingdom, the key hours are 00:00 GMT for the first Eastern polls, 01:00 to 02:00 GMT for the Central and Mountain states, and 04:00 GMT for the Pacific coast, where polls close at 8:00 p.m. PST.
Ships, ports and scheduled departures
Transatlantic crossings
A container ship leaving a New Jersey port at 15:00 EST departs at 20:00 GMT. A crossing of about seven days arrives at a British port at the same hour GMT a week later, subject to weather. The five-hour difference matters at the berth, where tugboats and pilots are booked in the local time of the port.
Documents
Bills of lading and customs notices carry local times. If you need a single timeline for a claim, convert every entry to GMT or UTC. A “convert EST to GMT” calculation for the departure and a separate one for the arrival cover the whole story.
Time zone names that look like EST
Other abbreviations
Australia has its own Eastern Standard Time, which is UTC+10. If a message from Sydney says “EST”, it means something very different from the American meaning. The same goes for a few other labels, such as CST for China or Cuba and IST for India, Ireland or Israel.
How to avoid the mix-up
Prefer the UTC offset in documents that cross borders: UTC−5 for EST, UTC−4 for EDT. When you receive a time with an ambiguous label, ask what the city is.
Checklist: how to convert EST to GMT
Before
Convert to 24 hours
Turn 8:15 p.m. into 20:15 so the addition is straightforward.
Check the label
If the sender wrote ET, find out whether it is EST or EDT on that date.
After
Add five hours
If the result passes 24:00, subtract 24 and move to the next day.
State both clocks
When you finish, publish the answer in both zones, so that nobody has to convert EST to GMT again, for example “13:30 GMT / 8:30 a.m. EST”.
A full-day lookup table in a.m. and p.m.
From dawn to bedtime
6:00 a.m. EST is 11:00 GMT. 8:00 a.m. is 13:00. 10:00 a.m. is 15:00. Noon is 17:00. 2:00 p.m. is 19:00. 4:00 p.m. is 21:00. 6:00 p.m. is 23:00. 8:00 p.m. is 01:00 the next day. 10:00 p.m. is 03:00 the next day. 11:30 p.m. is 04:30 the next day.
How to use it
Find the Eastern hour in the left column, read the Greenwich hour in the right, and check whether the date has moved. If you are going to convert EST to GMT dozens of times, print the table and keep it near the phone.
Timestamps with an offset in them
Reading −05:00
Many applications write times in the ISO form 2026-01-13T09:00:00-05:00. The part after the clock is the offset from UTC, here minus five hours, which is the Eastern Standard Time offset. To turn it into Greenwich time, add five hours and replace the offset with Z: 2026-01-13T14:00:00Z. The date moves only if the clock reaches 24:00.
In summer
The same city in July would write -04:00. A tool that reads the offset can convert EST to GMT without knowing anything about American clock rules, because the offset already carries the answer.
The Monday after each American clock change
Spring
On Monday 9 March 2026 the United States has just moved to EDT. A call that was at 10:00 EST the week before, which was 15:00 GMT, is now at 10:00 EDT, which is 14:00 GMT. A British participant who kept the old time in the diary arrives an hour late, or an hour early if the organiser recalculated.
Autumn
On Monday 2 November 2026 the United States has just moved back to EST. A call at 10:00 Eastern is 15:00 GMT again, having been at 14:00 GMT the week before. The best safeguard is to publish the time in GMT or UTC and let each person convert it.
Parcels, carriers and delivery times
Tracking pages
Carriers in the United States stamp tracking events in local time. “Delivered 3:42 p.m.” in Atlanta in January corresponds to 20:42 GMT. A parcel marked “out for delivery at 8:05 a.m.” in Boston left the depot at 13:05 GMT. Lined up this way, a chain of events reads as a day with a clear order.
Cut-off hours
A courier that accepts same-day pickup requests until 5:00 p.m. EST accepts them until 22:00 GMT. A British sender who books a pickup at 22:30 GMT will find the request goes into the next day’s queue.
Language habits that cause confusion
“Eastern” and “London time”
Americans say Eastern, Central and Pacific. Britons say London time, or GMT in winter and BST in summer. Neither habit mentions the date, and neither says which clock exactly. A person who writes “10 a.m. Eastern, 3 p.m. London” in July is correct for 10:00 EDT and 15:00 BST, but the same words in January describe 10:00 EST and 15:00 GMT.
Why this still works
The five-hour gap holds in both seasons, so the pair of numbers is stable even when the labels change. The risk is limited to the four mismatched weeks, when the numbers themselves change. Use the “convert EST to GMT” calculation on this page for the winter label and take one hour off the answer when New York is already on summer time and London is not.
Common mistakes when you convert EST to GMT
Subtracting instead of adding
London is ahead of New York, so the GMT number is larger. If the result is smaller than the input, the sign was wrong.
Mixing up a.m. and p.m.
A midnight deadline at “12 a.m.” is at the start of the date, not the end. Make sure which one the sender means before you convert EST to GMT.
Ignoring the date change
From 19:00 EST onward the answer falls on the next date in Greenwich. Do not copy the original date.
Using five hours in the mismatched weeks
Between 8 and 28 March 2026 and between 25 and 31 October 2026, add four hours when you convert EST to GMT from the current Eastern clock.
Frequently asked questions
How many hours do I add to EST to get GMT?
Five hours.
What is 8:00 p.m. EST in GMT?
01:00 GMT on the following day.
How do I convert EST to GMT quickly?
Add five to the twenty-four-hour value, then move to the next date if the total reaches 24.
Is EST the same as ET?
No. ET covers both EST in winter and EDT in summer.
Does the page store my times?
No. Everything happens in your browser.
More time zone converters
Related pages: Convert EST to UTC, Convert EST to EET, Convert WET to GMT, Convert CST to GMT, Convert GMT to WET, Convert WET to EST, Convert PST to EST, Convert EST to WET, Convert GMT to EET. The opposite direction is Convert GMT to EST.
To convert EST to GMT, then, add five hours, check the date, and keep in mind the four weeks a year when the gap is smaller. It is done on your own device, with no sign-up and no upload.