GMT — Greenwich Mean Time
See what GMT means, where it is used, how it relates to DST, and convert GMT to other time zones.
Countries: Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, United Kingdom
How to Convert GMT to Other Time Zones
Open the GMT converter page: Go to https://www.xconvert.com/time-converter/gmt-time-zone to load the visual comparison grid with GMT / Greenwich Mean Time already shown as the base row. This page is useful when you need to line up a London operations call, check shipping coordination with Accra or Abidjan, or compare UK-based schedules with teams working in IST.
Add comparison cities: Click “+ Add City” and search for cities that matter to your schedule, such as London, Dublin, and Mumbai if you are coordinating finance, support, or software work between the UK, Ireland, and India. You can also add Accra or Abidjan for West African trade and logistics, since both run on GMT year-round and are common reference points for regional business hours.
Select a time range on the grid: Click “Select” to enter selection mode, then drag across the GMT row to highlight a block such as 9:00 AM to 11:00 AM GMT. That same window is 2:30 PM to 4:30 PM IST, which makes it practical for a same-day handoff with an India team; if you drag 4:00 PM to 6:00 PM GMT, you will see it becomes 9:30 PM to 11:30 PM IST, which is usually too late for routine meetings.
Export and share the result: After selecting the range, use the export options shown below the grid: ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is especially useful when a UK-based manager wants to send a confirmed meeting slot to colleagues in India and West Africa so each person sees the event in local time without manually converting GMT.
About Greenwich Mean Time (GMT)
GMT stands for Greenwich Mean Time, the mean solar time at the Royal Observatory in Greenwich, London. Its exact standard offset is UTC+0:00, meaning it is aligned with Coordinated Universal Time with no positive or negative hour difference during standard time.
GMT is used as a civil time reference in a wide set of countries and territories, especially in West Africa and the British Isles during part of the year. Countries and regions associated with GMT include Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, and the United Kingdom. Important cities on this offset include Abidjan, Abobo, Bouaké, Daloa, San-Pédro, Accra, Kumasi, Tamale, Takoradi, and Atsiaman.
GMT is also closely tied to international scheduling because it serves as a baseline for comparing other time zones. Against IST, GMT is 5 hours 30 minutes behind, so when it is 9:00 AM GMT, it is 2:30 PM IST. That difference matters for real use cases such as UK-India outsourcing, software development standups, consulting calls, and customer support coverage, where the overlap window is usually strongest from late morning GMT to mid-afternoon IST.
Several abbreviations share the same UTC+0 offset at different times or in different regions, including AZOST, EGST, WET, WT, and Z. Even when offsets match numerically, the actual time zone rules can differ by location and season, so a visual comparison is safer than assuming every UTC+0 label behaves identically year-round.
GMT and Daylight Saving Time
For Greenwich Mean Time itself, the standard offset is UTC+0 and DST is false in the sense that GMT as a named standard time does not include a daylight saving adjustment. However, some places commonly associated with GMT, especially the United Kingdom, Ireland, Guernsey, Jersey, and Isle of Man, do not stay on GMT all year; they switch seasonally to British Summer Time (BST) or Irish Standard Time at UTC+1.
In the current year, 2026, the seasonal change for the UK and related Crown Dependencies occurs on 29 March 2026, when clocks move forward by one hour at 1:00 AM UTC, changing from GMT (UTC+0) to BST (UTC+1). They switch back on 25 October 2026 at 1:00 AM UTC, returning from BST to GMT. This means that a meeting set for 10:00 AM in London is 10:00 AM GMT in January, but 10:00 AM BST = 9:00 AM GMT in July.
By contrast, many African locations on GMT such as Ghana, Ivory Coast, Senegal, Sierra Leone, and Togo do not observe daylight saving time and remain on UTC+0 all year. That distinction is important for aviation schedules, remote team calendars, and trading coordination, because a London-to-Accra time comparison is equal in winter but becomes London one hour ahead of Accra during the summer DST period.
Frequently Asked Questions
What does GMT stand for?
GMT stands for Greenwich Mean Time, named after Greenwich in London, where the Royal Observatory established the prime meridian reference used in global timekeeping. In practical use, GMT refers to the UTC+0 standard time used in several countries and as a common reference point for international scheduling, navigation, and broadcasting.
Is GMT the same as IST?
No. GMT is UTC+0, while IST (India Standard Time) is UTC+5:30, so IST is 5 hours 30 minutes ahead of GMT. For example, when it is 8:00 AM GMT, it is 1:30 PM IST, which is why UK-India meetings are often scheduled in the late morning UK time to fit both workdays.
Which cities use GMT?
Cities and metro areas on GMT include Abidjan, Accra, Kumasi, Tamale, Takoradi, Abobo, Bouaké, Daloa, San-Pédro, and Atsiaman, along with London during the part of the year when the UK is on standard time. These cities are important in sectors such as shipping, cocoa trade, mining, telecom, public administration, and regional aviation, especially across Ghana and Ivory Coast.
What is the UTC offset for GMT?
The exact UTC offset for GMT is UTC+0:00. That means GMT is neither ahead of nor behind UTC during standard time, making it one of the most commonly used baseline references for comparing time zones across Europe, Africa, Asia, and the Americas.
When does GMT change?
Strictly speaking, GMT itself does not change, because it is the standard UTC+0 time reference. What changes is that some countries associated with GMT, such as the United Kingdom and Ireland, move to a summer time system; in 2026, they switch on 29 March 2026 to UTC+1 and return on 25 October 2026 to GMT (UTC+0).
Is GMT the same as UTC?
GMT and UTC are often treated as equivalent for everyday scheduling because both are commonly shown as UTC+0. Technically, UTC is the modern atomic time standard used worldwide, while GMT is historically based on mean solar time at Greenwich; for business calls, flight planning, and calendar events, the two are usually interchangeable unless a system specifically distinguishes seasonal legal time rules.
Which countries use GMT all year?
Several countries use UTC+0 year-round without daylight saving changes, including Ghana, Ivory Coast, Senegal, Sierra Leone, Togo, Liberia, Guinea, Guinea-Bissau, Mali, Mauritania, Burkina Faso, Gambia, Sao Tome and Principe, and Iceland. This consistency is useful for multinational operations because schedules with these countries do not shift seasonally, unlike meetings involving the UK or Ireland.
How far behind IST is GMT?
GMT is 5 hours 30 minutes behind IST throughout the year because India does not observe daylight saving time. So if a support team in Mumbai starts work at 9:00 AM IST, it is only 3:30 AM GMT, while 1:00 PM GMT corresponds to 6:30 PM IST, often a more realistic overlap for project reviews and client calls.